Hi splitscreen,
Welcome to the Mattress Forum! 
I’m assuming that you’ve read the mattress shopping tutorial but two of the most important links in the tutorial that I would especially make sure you read are post #2 here which has more about the different ways to choose a suitable mattress (either locally or online) that is the best “match” for you in terms of “comfort” and PPP (Posture and alignment, Pressure relief, and Personal preferences) that can help you assess and minimize the risks of making a choice that doesn’t turn out as well as you hoped for and post #13 here which has more about the most important parts of the “value” of a mattress purchase which can help you make more meaningful quality/value comparisons between mattresses in terms of suitability (how well you will sleep), durability (how long you will sleep well), and the overall value of a mattress compared to your other finalists (based on all the parts of your personal value equation that are most important to you).
Since PPP and how well you will sleep on a mattress is the most important part of the “value” of a mattress purchase when you are testing mattresses locally then the most reliable way to know whether a mattress is a good “match” for you in terms of PPP is your own careful testing (hopefully using the testing guidelines in the tutorial post).
When you can’t test a mattress in person then the most reliable source of guidance is always a more detailed conversation with a knowledgeable and experienced retailer or manufacturer that has your best interests at heart who can help “talk you through” the specifics of their mattresses and the options they have available that may be the best “match” for you based on the information you provide them, any local testing you have done or mattresses you have slept well on and liked that they are familiar with, any special considerations you may have, and the “averages” of other customers that are similar to you. They will know more about helping you to “match” their specific mattress designs or firmness options to different body types, sleeping positions, and preferences or even to other mattresses that they are familiar with than anyone else so that in combination with your own personal testing you can make the “best possible” choice with the highest chance of success.
[quote]PLB “Serenity” Layers:
- Pressure Relief Talalay SS Latex: 1"
- Support Talalay S Latex: 6"
- Stabilization Base: 1"[/quote]
The Serenity is the same as the PLB Pamper and these are old specs. You can see the current specs of the Serenity/Pamper in post #2 here. Having said that … the actual specs won’t tell you whether the mattress is a good match for you in terms of PPP which is the most important part of the "value) of a mattress purchase and is the part that you need to confirm with your own personal testing or experience. The Pamper uses high quality materials and there are no weak links in the design that would have a detrimental effect on the durability or useful life of the mattress.
SavvyRest offers the choice of soft, medium, or firm layers in either organic Dunlop or 100% natural Talalay. While they don’t disclose the specific ILD of their layers you can see their ILD range in post #2 here.
It’s not unusual that what “feels good” based on the more subjective “showroom feel” of a mattress can be different from what you will sleep best on over the longer term and what you really “need” which is one of the reasons that I suggest using the testing guidelines in the tutorial rather than just going by “feel” alone.
The Brooklyn Bedding BestMattressEver certainly uses high quality materials and there are no weak links in the mattress in terms of durability. There is more about what I call “simplified choice” mattresses in post #1 of this topic and there is more about the BestMattressEver and some of the others in post #2 of the same topic.
[quote]Generally, I was also advised to move up from a Twin to a Twin XL, since the larger cousin can be paired up to create a King-size equivalent for the future.
While this was marketed to me as a selling feature at the other places, BB did not offer the same option of “upgrading” to a King, unless I simply wanted to set two separate Twin XLs together, side-by-side. Ideally, I’d like to buy a Twin XL now, and the guts of another Twin XL in the future, along with a King cover to wrap it together. At least, that’s how it was explained to me. I could use some guidance on whether this is really as good an idea as others were making it out to be.
[/quote]
If you ever need a larger sleeping area and you have a twin XL mattress then you can add a second twin XL beside it and have a king size rather than an “odd” size that needs custom sheets and bedding. I’m not clear what they mean by “upgrading” because if you purchase a twin XL and want to “upgrade” to a king size that was a whole mattress (that isn’t two twin XL mattresses placed side by side) then you could purchase new twin XL layers for the other side to make up a king size but you would need to also buy a new mattress cover which can be somewhat costly. There is more about the pros and cons of a mattress that has side to side split layering in post #2 here and there is also more about two separate twin XL mattresses that are placed together and used as an Eastern King size in post #8 here and in this topic.
These are called “component” mattress where one or more of the layers can either be rearranged or exchanged if you need to “fine tune” your comfort/pressure relief or the support/alignment on the mattress after a purchase. SavvyRest is one example of these although there are many others as well. The tutorial post includes a link to a list of the members here that sell mattresses online.
If you are looking at an online purchase rather than a local purchase then the the mattress shopping tutorial includes a link to a list of the members here that sell mattresses online (in the optional online step) that all compete well with the best in the industry in terms of their quality, value, service, transparency, and knowledge and many of them sell latex and latex hybrid mattresses that use different types and blends of latex (including organic Dunlop if an organic certification is important to you) that have a wide range of different designs, options, features, return and exchange policies, and prices that that would be well worth considering as well Post #3 here includes a list of the ones that sell component latex mattresses that are generally in lower budget ranges than the SavvyRest you were considering.
The first “rule” of mattress shopping is to always remember that you are the only one that can feel what you feel on a mattress and there are too many unknowns, variables, and personal preferences involved that are unique to each person to use a formula or for anyone to be able to predict or make a specific suggestion or recommendation about which mattress or combination of materials and components or which type of mattress would be the best “match” for you in terms of “comfort” or PPP (Posture and alignment, Pressure relief, and Personal preferences) or how a mattress will “feel” to you or compare to another mattress based on specs (either yours or a mattress) or “theory at a distance” that can possibly be more accurate than your own careful testing (hopefully using the testing guidelines in step 4 of the tutorial) or if you can’t test a mattress in person then your own personal sleeping experience (see mattress firmness/comfort levels in post #2 here).
I or some of the more knowledgeable or experienced members of the site can certainly help you to narrow down your options, help you focus on better quality/value choices that are available to you either locally or online, help you identify any lower quality materials or weak links in a mattress you may be considering, act as a fact check, answer many of the specific questions you may have along the way that don’t involve what you will “feel” on a mattress, and help with “how” to choose but only you can decide which specific mattress or combination of materials is the best match for you based on all the parts of your personal value equation that are most important to you.
The choice between different types and combinations of materials and components or different types of mattresses (see this article) are more of a preference and a budget choice than a “better/worse” choice (as long as all the materials and components in a mattress are durable enough for your body type).
All the layers and components in a mattress (including the cover) will affect the feel and performance of every other layer and component and the mattress “as a whole” and mattress manufacturers generally try to differentiate their mattress from the mattresses made by other manufacturers and don’t normally try to “match” another mattress that is made by a different manufacturer so it’s unlikely that you will find another local mattress that is specifically designed to “match” the Pamper/Serenity and has exactly the same specific layers and components in their design although you may find other mattresses that also use blended Talalay latex that have very similar specifications (the type and blend of latex, layer thicknesses, layer firmnesses, and a similar cover) with some of the online manufacturers .
That doesn’t mean that there aren’t other mattresses that would be just as good or even better in terms of “comfort” and PPP (Posture and alignment, Pressure relief, and Personal preferences) … only that they may not have the same “feel” or exactly the same design and you may prefer some over others. Different people can also have very different opinions about how two mattresses compare because of differences in their body weight, sleeping style, or individual circumstances and sensitivities so the only way to know how two mattresses compare “for you” will be based on your own careful testing or personal experience.
I don’t keep a record of the individual mattresses that the retailers and manufacturers in the hundreds of forum lists throughout the forum carry on their floor (it would be a bigger job than anyone could keep up with in a constantly changing market) but checking their websites and making some preliminary phone calls to the retailers/manufacturers that are on the list that are in reasonable driving distance is always a good idea before you visit any store anyway. This will tell you which of them carry mattresses that would meet your specific criteria, are transparent about the quality and durability of the materials in their mattresses (see this article), and that carry the type of mattresses that you are interested in testing in the budget range you are comfortable with. Once you have checked their websites and/or talked with the ones that interest you then you will be in a much better position to decide on the ones that you are most interested in visiting based on the results of your preliminary research and conversations.
The most effective way to choose is to follow all the steps and guidelines in the tutorial post one at a time (along with the online step if you are also looking at online options) which will give you the best chance of making a successful purchase that is the most suitable, the most durable, and that meets all the other criteria that are most important to you.
Phoenix