Hi sreeDallas,
There are “many roads to Rome” meaning that there may be many different layering combinations that feel the same or similar to you. If you test the mattresses carefully and limit your testing to only the mattresses that they can provide the details of every layer in the mattress then I would let your body tell you which felt similar rather than specs which can be misleading when it comes to how a mattress may feel. I would avoid “brand” shopping and focus on the materials in your mattress along of course with how it feels and performs.
You can see the layering of the Genius here and it has 2.75" of memory foam (gel memory foam is a type of memory foam) over a 2" layer of firmer polyfoam over a “regular” firm polyfoam base layer. A similar mattress “in theory” would have about 3" of memory foam over a few inches of firmer polyfoam (to provide the firm feel that “comes through” the memory foam) over a regular polyfoam support core. It may be quite surprising though that a different construction may feel similar to you. The goal is to get the “feel” and performance you want using higher quality more durable materials at a lower cost than the iComfort.
Again … no matter which merchant you are considering … I would focus only on mattresses where the details of every layer in the mattress is available to you regardless of brand so you can make meaningful comparisons between mattresses. I would also tend to call any merchant I was thinking about visiting before I went there to let them know the types of mattress I was considering and make sure they had something mattresses for me to test and that I was happy with the information they provide and the way they treat their customers on the phone.
Phoenix