Hi EZ4HZ,
Dreamfoam sells through Amazon but some of their mattresses can be either Amazon fulfilled (for a few of them) or Dreamfoam fulfilled (for all of them). They are also sold direct through their Dreamfoam site here.
If you purchase through Amazon with Amazon fulfillment then if you return the mattress it would be subject to the Amazon large items return policy (see post #11 here).
If you purchase through Amazon but it is Dreamfoam fulfilled then there is no return policy (or at least you would pay the full cost of common carrier returns which can be quite costly). Dreamfoam fulfilled mattresses are usually less costly than Amazon fulfilled mattresses (Amazon usually adds some additional costs to the mattresses they fulfill).
If you purchase through the Dreamfoam site then they have a 45 day comfort guarantee (see the bottom right corner of their site) and there is also a 10% discount available at the moment (see their facebook page here).
Post #2 here has more about making final choices when you are down to finalists that are comparisons between “good and good” and there are no clear winners between them.
Phoenix