Hi jstephens,
No problem. This thread has become a kind of “catch all” thread anyway 
There is an analysis and review of the iComfort lineup here in case you haven’t seen it. Overall, like most of the major brands they don’t have great value and some of the models would also be “risky” for many people. They tend to cater to a showroom feel that people like in the short term but not so much on what people need (good alignment along with the pressure relief they do provide) in the longer term.
I also believe that airbeds are among the worst choices and value of all and there is more about the reasons why here.
Some of the guidelines that will help you in finding better quality and value and in avoiding most of the traps and pitfalls of mattress shopping (such as believing when the salespeople say that the Stearns and Foster are really a “latex” mattress or comparable to other lower cost and higher quality latex options) are in this article. Not only do they use the least expensive latex available (blended Dunlop) … their premium models such as this still contain over 4" of lower quality polyfoam in the upper layers of the mattress (which is the weak link of the mattress). With a mattress like this you are not sleeping on latex at all but on much cheaper polyfoam.
Original mattress factory is much higher quality and value than any of the major brand mattresses IMO. Both of their latex mattresses contain only 1" of polyfoam in the comfort layers (which is within the maximum I normally suggest) and they use a higher quality of latex than the Stearns and Foster.
Their Serenity is also a very high quality memory foam mattress however because they only have one model (and only two latex models) … it’s important to make sure that the models they make are suitable for your needs and preferences regardless of their quality and value.
If you go to test these mattresses … I would also make sure you test them on a firm foundation (or on an adjustable bed which are also firm and non flexible) because they tend to put their mattresses on “active” box springs which I don’t believe is as good an idea and will certainly change the feel compared to a more “normal” rigid foundation that is usually used for latex and memory foam mattresses.
Gel tends to slightly reduce heat through convection (like putting your and on a marble countertop) but of course this would only be effective if the gel foam was on top. Some of the gel foams are also more breathable (more open cell structure) which means that they can regulate temperature better than some of the “slower” more heat sensitive and less open cell memory foams. There are also many non gel memory foams that are also more open celled and breathable that don’t contain gel. None of them are as cool sleeping or as open celled as better quality latex though.
How far you sink into any foam and how closely it conforms to your body and the quilting/ticking on top of the mattress will also directly affect the sleeping temperature of a mattress for any particular individual.
Post #2 here includes some of the better options in and around the Atlanta area that I am aware of.
A final suggestion that may be worth considering if the only issue is that your mattress is too firm but hasn’t developed any other “issues” (you have changed more than the mattress) is that a softer good quality topper (generally either latex or memory foam) may also be a good solution.
Phoenix