Hi Meegs, if it's possible it might be worth while finding a mattress store where you can try latex personally. Even if it's a bit out of the way, maybe check to see what other places are in the area and make a day of it so the trip isn't such a chore going well out of your way 'just' to try mattresses. Latex and memory foam really are quite different. My first time trying latex was different from most anything else I had to compare to like innerspring, memory foam or a waterbed. Even softer latex, depending how the pressure/weight is applied to it it can react very differently.
Sitting on the edge of a softer mattress (latex) it seemed to give way more than I was used to. As soon as I laid down as I would sleeping with my body/weight spread out over a much larger area, it was a lot more supportive than I could have imagined. Being the most used to innersprings where there seems to be 'resistance' to pressing down on it, I could press down with my hand and easily compress thinner layers (6" of soft latex, far softer/thinner than would be used for a mattress). I laid on it just to see and with my body spread across it, still didn't sink through it.
For as elastic as latex is, in the firmer ild's it can be firm/supportive enough that it can feel like laying on a solid slab with very little 'sink in'. Very difficult to describe which is why testing it out would be the best option. You may really like it, you may not. Between the cost of a quality mattress and the impact it has on a good night's sleep, better to know if possible than go blind into it. How it feels compared to the tempurpedic you're familiar with may change greatly from one person to another. I researched for months prior to being able to try one personally, ordered samples of latex to try and get a feel and it just wasn't the same as a full mattress. If I'd gone with just that information alone I'm almost certain I would have ended up with a mattress far firmer than I would have been happy with. Good luck on your mattress hunt.