Hi prepballfan,
I think it’s probably safe to say that most people that have read the information you read would be very nervous about dealing with them as well.
I’m assuming that you’ve read the mattress shopping tutorial (which is the first place to start your research) but 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” 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 (including the price of course and the options you have available after a purchase to exchange or return the mattress if your choice doesn’t turn out as well as you hoped for … especially if you can’t test the mattress before a purchase).
If you are looking at online options then the mattress shopping tutorial includes several links to lists of many of the better online options I’m aware of (in the optional online step) that include many different types and categories of mattresses (including memory foam) in a wide range of budgets, firmness levels, and return/exchange policies that would be well worth considering.
If you are also interested in local options then if you let me know your city or zip code I’d be happy to let you know about the better options or possibilities I’m aware of in your area as well.
Phoenix