Hi FoCoMom,
Just in case you haven’t read it yet … the first place to start your research is the tutorial post here which has all the basic information, steps, and guidelines that can help you make the best possible choices … and know how to avoid the worst ones.
If your mattress is still in good condition and has no soft spots or sagging then it may be worth adding a topper to provide the additional pressure relief and “comfort” that you need which would be considerably less than a completely new mattress. Post #2 here and the topper guidelines it links to can help you choose the most suitable topper. While there is always some risk involved in choosing a topper that works well in combination with both your mattress and you when you can’t test the combination in person … it also has the advantage of being replaceable so if the topper softens and breaks down before the rest of the mattress (which is likely because the top layers of a mattress or sleeping system are usually the “weak link” of a mattress) then it can be easily replaced without replacing the complete mattress and a topper will also extend the life of the mattress underneath it.
The most important part of choosing a mattress in a showroom is careful and objective testing for PPP (Posture and alignment, Pressure relief, and Personal preferences). This is the part that only you can decide because there are too many unknowns, variables, and personal preferences involved for for anyone else to be able to recommend a mattress for someone else based on personal information, mattress specs, or theory at a distance and nobody else can feel what you feel on a mattress (see mattress firmness/comfort levels in post #2 here). The mattress testing guidelines that are linked in the tutorial post along with some guidance from an experienced salesperson can help you decide which mattress is the best match for you in terms of PPP.
There is also some information in post #2 here about the variables that can affect sleeping temperature and a different mattress protector or sheets and bedding can solve many temperature regulation issues.
Outside of careful and objective testing … the most important part of choosing a new mattress is knowing the quality of all the materials and components inside it so that you can make sure there are no weak links in the mattress and make more meaningful comparisons to other mattresses based on the materials and components inside them. A good retailer or manufacturer will normally be able to provide you with the information you need (see this article) and if you can list the specifics of either the Sherwood Ambiance Luxury Plush, the Lumina Radiance Plush, or the Urban Organics Eco Sensation on the forum I’d be happy to make some comments about the quality of the materials inside them or help you identify any weak links they may have in their materials or design (using the guidelines in post #4 here)
Once you have decided on your finalists and are making final choice between “good and good” then you will be in a much better position to decide which of them is the best match for you based on the parts of your personal value equation that are most important to you.
You’ve probably seen this but just in case you haven’t … the better options and possibilities I’m aware of in the Fort Collins area (which includes Urban Organics) are listed in post #4 here.
Phoenix