I bought a latex mattress about 5 years ago after 20+ years on a waterbed. It's amazing, and holding up very well. I bought it from a discount mattress place in Minneapolis after checking out dozens of mattresses around town. Sorry; I don't remember the brand. It even made a backache disappear overnight rather than worsen. I'm still astounded by that.
My primary advice is to lay on lots of mattresses and listen to what your body tells you. For me, the mattresses that held the most appeal were the ones where my body "vanished" when I laid on them. On most mattresses, I could feel my hips, my legs, my shoulders, my back....there would be one or more pressure points that I'd be aware of. Just what those points would be varied from mattress to mattress.
When I first laid on a mattress with a memory foam topper, it was like my body disappeared (in a good way). The pure memory foam mattresses were too firm. The latex mattress turned out to be by far the best...for me. What's best for you may well be something completely different.