Hi cubby,
I would be very cautious about using reviews as a significant part of your mattress research (see post #13 here). Reviews rarely mention the quality of the specific materials in a mattress (a mattress is only as good as it’s construction and materials and the name of the manufacturer has little relevance), they are generally written by people who have little knowledge about mattresses or what they purchased, they say little to nothing about which mattress may be suitable for you (each person is unique and a mattress that works well for one person may be completely unsuitable for another), and they are usually written so soon after a purchase that they don’t usually include much about the longer term experience on a mattress.
I think that there are many consumers that feel the same way. I think that one of the most important parts of a successful mattress purchase is choosing the retailer or manufacturer you are dealing with (step 3 in the tutorial post) as carefully as you choose the mattress. Dealing with a knowledgeable, experienced, and transparent retailer or manufacturer (either locally or online) that can “inform and educate” you more than “sell” you and that puts your interests and satisfaction above their own can turn mattress shopping from an exercise in frustration into a much simpler and more enjoyable experience 
Phoenix