Hi aron82e,
Comfort is a very subjective thing and different people will have very different opinions about what is comfortable for them. Any comparison between memory foam ad latex is also very much of an apples to oranges comparison because they are both very different in terms of performance and feel.
I should mention as well that Tempur Foam is just viscoelastic polyurethane just like all the other memory foam formulations that are available.
For most people however … the ability of a material to relieve pressure is one of the biggest parts of “comfort” and in these terms they are very equivalent.
There are many other differences between then however that are also important parts of comfort for many people including the ease of movement on the surface, resilience and response rate, temperature regulation and ventilation and the overall “feel” and response of both which are very different. Memory foam tends to be a more “in the mattress” feel while latex tends to be a more “on the mattress” feel.
While testing or sleeping on both is really the only way for you to know which one is most comfortable for you (as opposed to someone else who may have different ideas) … you can read more about the pros and cons of memory foam in this article and the pros and cons of latex in this article which may help.
While I think that some people may buy latex because of it’s natural qualities and the lack of safety and offgassing issues (although the most popular latex isn’t even natural but blended) … I think the majority of people buy it because it’s very comfortable for them and they prefer its feel and performance over other materials including memory foam.
Innersprings are a support system (not a comfort system) and not usually used in the comfort layers (except for microcoils) so how an innerspring mattress feels in terms of comfort is primarily based on the foam that is used over the innerspring and its layering and only secondarily on the type of innerspring that is used as the support system and how it interacts with the comfort layers of the mattress.
Post #2 here has more information about how each may compare in terms of a support system. I have often mentioned on the forum that some of the most knowledgeable people I know that could sleep on any type of mattress that they wanted to have very different preferences. Some of them prefer an innerspring with latex comfort layers, others prefer all latex, others yet prefer memory foam over polyfoam (a typical memory foam mattress), and others yet prefer an innerspring with natural fibers layered on top of it. Once again they are more “different” than “better/worse” comparisons and each person will have their own preferences and the most reliable way to see which type of support system you prefer in your mattress in combination with which type of comfort layers is through personal testing.
With your weight … the firmness of whatever support system you choose (so that your heavier parts are “stopped” before they sink in too far) and the firmness and durability of the comfort layers which provide you with pressure relief and much of your “comfort” (which are also generally the first to soften and wear out) will also be very important.
Phoenix