Hi lenyc,
Unfortunately … you are getting some bad or at least some very risky advice here. I would avoid Simmons and any other major manufacturer that uses low quality materials in their mattresses (see the guidelines here) and I would also be very cautious about buying a mattress / topper combination where you can’t test the specific combination in person (see post #2 here). While your chiropractor may know a lot about backs … he doesn’t seem to be particularly knowledgeable about mattresses :dry:
The first place I would start your research is the mattress shopping tutorial here which has all the basic information, steps, and guidelines that can help you make the best possible choice … and know how and why to avoid the worst ones.
You can test for edge support in person to see whether it is OK for you but the Casper uses good quality materials that would be a durable choice for most people as long as you aren’t in much higher weight ranges (see the foam quality guidelines here).
The Berkeley Ergonomics mattresses use very high quality materials and they are a better quality/value choice than most other mainstream mattresses that are in a similar budget range or many other similar types of mattresses that are in a higher price range although I certainly understand that they are in a higher budget range than some people would be comfortable with regardless of their quality or “value”. There is more about the most important parts of the “value” of a mattress purchase in post #13 here that can help you make more meaningful comparisons between mattresses.
As may already know … Arizona Premium is one of the members of this site which means that I think very highly of them and they compete well with the best in the industry in terms of their quality, value, service, and transparency. They would certainly be well worth including in your research. The tutorial post also includes a link to a list of the members here that sell online (in the optional online step) that would be well worth including in your research and if you are looking at innerspring/latex mattresses then post #2 here also has some options that may be well worth considering as well.
You can see my thoughts and an analysis about Saatva in post #1 here and while they compare well to most mainstream mattresses … for most people they would not be in the same “value” range as many of the other options that are available to you. A forum search on Saatva (you can just click this) will bring up much more information and feedback about them.
I’m guessing you’ve seen this as well but just in case you haven’t then the better options or possibilities I’m aware of in the New York City area are listed in post #2 here.
Phoenix