The tricky thing about mattresses is that no particular one suits everybody the same. Not everyone can sleep on a latex mattress. Not everyone can be comfortable on a foam mattress either.
It's one of the curious things about people. Between the various body types and sleeping styles, it's very hard to say just what exactly will suit someone.
It may sound like a bit of a cop-out to say, but the best way to buy a mattress is to find one that makes you comfortable. Choosing the right mattress has a lot more to do with knowing your sleeping style than it has to do with anything else.
That said, if you know it, you'll be able to find the right mattress for you