Hi s.guo1,
Welcome to the Mattress Forum! 
You’re very welcome.
If you’ve been doing any reading on the site, you’ll know that while I can certainly help with “how” to choose … It’s not possible to make specific suggestions or recommendations for either a mattress, manufacturers/retailers, or combinations of materials or components because 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”, firmness, or PPP or how a mattress will “feel” to you or compare to another mattress based on specs (either yours or a mattress), sleeping positions, health conditions, or “theory at a distance” that can possibly be more reliable than your own careful testing (hopefully using the testing guidelines in step 4 of the tutorial) or your own personal sleeping experience (see mattress firmness/comfort levels in post #2 here).
However, I can provide some commentary on the models you’ve mentioned.
Ikea isn’t complete in the specifications, but this mattress uses 2.2 lb polyfoam and synthetic latex (both would be good quality materials), but the thickness and combinations aren’t listed, and that’s something you’d want to find out.
Regarding reviews, those are the least reliable way to purchase a mattress, and I would advise against using those as any sort of manner in making your decision. While other people’s comments about the knowledge and service of a particular business can certainly be very helpful … I would always keep in mind that you are the only one that can feel what you feel on a mattress and I would be cautious about using anyone else’s suggestions, experiences or reviews on a specific mattress (either positive or negative) or review sites in general as a reliable source of information or guidance about how you will feel on the same mattress or how suitable or how durable a mattress may be for you. In many if not most cases they can be more misleading than helpful because a mattress that would be a perfect choice for one person or even a larger group of people in terms of comfort, firmness, and PPP may be completely unsuitable for someone else to sleep on (even if they are in a similar weight range). In other words … reviews or other people’s experiences in general won’t tell you much if anything about the suitability, quality, durability, or “value” of a mattress for any particular person (see post #13 here).
As for the mattress warranty, this again is more marketing than a reliable indicator of quality or durability. Warranties in general are not nearly as important to me as knowing the materials because the reason most people need to replace a mattress is not a manufacturing defect but the loss of comfort and/or support which is not covered by a warranty. Knowing the materials in a mattress will tell you how long the original qualities of a mattress will last relative to other types of materials.
A 365 day mattress return policy is nice, but again this is more marketing than something that has a considerable a value, as most people are able to determine within the first 30 days or so if a product is appropriate for their needs.
The 2.2 lb polyfoam would be a good quality material. I would recommend you refer to the durability guidelines here. I believe you are confusing polyfoam with memory foam, where 2.2 lb would be a lower quality memory foam.
The latex used in this mattress is Dunlop, but there isn’t complete information about the blend or certification information about this foam. A forum search on Lucid (you can just click the link) will bring up comments and feedback about them. Lucid is from China, and post #6 here is about mattresses imported from Asia or China which may have been compressed for long periods of time in either shipping or storage before being purchased, which in my opinion makes this a more risky purchase. Again, see above for my comments about reviews and warranty.
This mattress uses:
Comfort Layers: 2" 3.65 lb Avena polyfoam (20-26 IFD), 2" 3lb Memory foam (9 IFD)
Support Layers: 6" Polyfoam 1.8 lb density (32-38 IFD)
I would advise caution here, as the 2" of 3 lb memory foam is a potential weak link in this mattress. You can read more about Leesa in post #2 here. The 2" of 3.75 lb high performance “latex like” Avena polyfoam is good quality, but I would be cautious because of the 2" of 3 lb memory foam in the comfort layers which could be a weak link in the mattress in terms of durability. And you’re already aware of my advice to ignore reviews as any sort of a reliable indicator of the quality or appropriateness of any mattress for yourself.
As before, you’re considering the wrong things (reviews, warranty) when selecting a mattress. I’m assuming you’re mentioning the Loom & Leaf here by the price point you mentioned. This item has:
Comfort Layers: Soft solid gel lumbar layer, 2" Convoluted gel memory foam (4 lb density), 2.5" memory foam (5 lb density).
Support Layers: 2" Transition layer (1.5 lb or higher polyfoam material), 5.5" Polyfoam (1.5 lb or higher polyfoam).
I provide a caution here for higher weight ranges. Saatva wouldn’t disclose to me the density of the bottom two layers (see post #2 here) so I would treat them both as 1.5 lb density. They also use a thin lumbar layer of soft solid gel (not gel foam) on top of the gel memory foam for additional temperature regulation and to add additional zoning support under the heavier parts of the body that for some people can help with alignment. I would be cautious for those that are in higher weight ranges (more than the low 200’s or so) or perhaps even a little lower than this because of the lower density polyfoam layers and the 4 lb convoluted gel memory foam in the top layers.
This mattress used 100% NR Dunlop latex and wool, both high quality and durable materials. This item uses higher quality materials than the mattresses you’ve listed preceding it. As for the return fees, no return of a mattress is free, and the cost of returns as a percentage of overall sales and the shipping fees are built into the selling price of any online mattress with a return policy. Some manufacturers choose to include all of this in the final price, some choose to include some of it but still charge partial shipping (like Latex Mattress Factory), while others include none of the shipping fees for returns in their final price.
Like the Latex Mattress Factory product, this is a higher-quality item than the previous items you listed and this items uses 100% NR latex and wool, which are both durable and high-quality materials.
Both Latex Mattress Factory and Sleep on Latex are members of this site which means that I think very highly of them and that I believe that they compete well with the best in the industry in terms of their quality, value, service, knowledge, and transparency.
The overall value of a mattress compared to your other finalists is based on all the parts of your personal value equation that are most important to you (including the price of course and the options you have available after a purchase if your choice doesn’t turn out as well as you hoped for).
I’d recommend that you read the mattress shopping tutorial here if you haven’t already, which includes all the basic information, steps, and guidelines that can help you make the best possible choice … and perhaps more importantly know how and why to avoid the worst ones.
Two of the most important links in the tutorial that I would especially make sure you’ve 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”, firmness, and PPP 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.
While again nobody can speak to how any specific mattress will “feel” for someone else or whether it will be a good “match” in terms of comfort, firmness, and PPP because this is too subjective and relative to different body types, sleeping positions, and individual preferences, sensitivities, and circumstances and you are the only one that can feel what you feel on a mattress … outside of PPP (which is the most important part of “value”), the next most important part of the value of a mattress purchase is durability which is all about how long you will sleep well on a mattress. This is the part of your research that you can’t see or “feel” and assessing the durability and useful life of a mattress depends on knowing the specifics of its construction and the type and quality of the materials inside it regardless of the name of the manufacturer on the label or how a mattress feels in a showroom or when it is relatively new so I would always make sure that you find out the information listed here so you can compare the quality of the materials and components to the durability guidelines here to make sure there are no lower quality materials or weak links in a mattress that would be a cause for concern relative to the durability and useful life of a mattress before making any purchase.
Phoenix