Hi Howlin Hound,
I’m sorry to hear that your Casper mattress isn’t working out for you but the good news is that you had the foresight to purchase an online mattress that has a very good return policy so you had the chance to try it will little risk outside of the time and effort involved in testing it out and returning or donating it.
I certainly wouldn’t be using Stearns & Foster or Aireloom as a reference point for quality/value and as you can see in the guidelines here I would tend to avoid both of them along with any mattress where you aren’t able to find out the specifics of the materials inside them.
The first place I would start your research is the mattress shopping tutorial here which has all the basic information, steps, and guidelines that you will need to make the best possible choice … and more importantly know how to avoid the worst ones.
Your budget is quite low for a good quality latex/pocket coil hybrid and you may have some difficulty finding one locally that’s in your budget range but there are some latex/innerspring hybrids listed in post #2 here that would be well worth including in your research that you can use as reference points for quality/value and several of them are inside your budget.
Only you can feel what you feel on a mattress and there are too many unknowns, variables, and personal preferences involved for anyone to be able to predict whether any mattress will be a good match for you based on specs (either yours or a mattress), health conditions, individual circumstances, or “theory at a distance” (see mattress firmness/comfort levels in post #2 here) and the only reliable way to know whether any mattress is a good match for you in terms of PPP ( Posture and alignment, Pressure relief, and Personal preferences) is based on your own careful testing or actual sleeping experience.
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 and who can help “talk you through” the specific options they have available based on the information you provide them, any local testing you have done, and the “averages” of other customers that are similar to you. They will know more about “matching” their specific mattress designs to different body types, sleeping positions, and preferences (or even to other mattresses that they are familiar with) than anyone else.
There is also more about the different ways to choose a mattress (either locally or online) that is the most suitable “match” for your specific needs and preferences and how to identify and minimize the risks of making a choice that doesn’t turn out as well as you hoped for that are involved in each of them in post #2 here.
Outside of comfort and PPP … a mattress is only as good as it’s construction and the quality of the materials inside it regardless of the name of the manufacturer on the label. Most of the companies that you mentioned make high quality mattresses that don’t have any lower quality materials or “weak links” in their design but you may have some difficult finding out the specifics of the materials inside some of the Diamond mattresses you encounter.
You can read a little more about Gold Bond in post #4 here but once again the quality/value of any particular mattress will depend on the specifics of the materials and components that are inside it regardless of the name of the manufacturer.
None of the Berkeley Ergonomics mattresses have any lower quality materials or “weak links” in their design
The better options and possibilities I’m aware of in that are close to you in the Albany/Schenectady area (subject to the quality/value guidelines here) are listed in post #4 here.
The Springfield,Northampton list is in post #4 here
The list for Los Angeles in is post #2 here.
The list for San Diego is in post #2 here.
These will help you narrow down your options in each of the areas you mentioned and help you avoid the worst choices but you will need to make some phone calls to find out which of the options in each of the lists I linked carry one or more mattresses that fir your criteria and you would be interested in testing on their floor (I don’t keep a record of the individual mattresses that each of the retailers or manufacturers that are listed in the hundreds of local lists in the forum have on their showroom floor which would be more than anyone could keep up with in a constantly changing market).
If you are also considering online options then the tutorial post also includes a link to a list of the members here that sell mattresses online (in the optional online step) that would also be well worth including in your research.
Phoenix