A week in with this bad boy and I am LOVING it. I've not slept this well or soundly in a long time.
It's a PERFECT combination of soft and firm. I tend to be a side sleeper, and this thing is wonderful for that. I used to wake up with shoulder pain in my right shoulder if I spent the entire night on my right side. Now? No problem at all.
The one thing I have found is that I don't need nearly as many pillows with this mattress. I always slept with 4 -- a contour memory foam pillow that works well with my CPAP and side sleeping, a pretty bulky non-memory foam pillow, and two thinner pillows. Now I really only need the memory foam pillow unless I'm using all of them to prop up my back when I'm reading in bed. If I try to use more than 1 pillow to sleep I find that my neck and bag get severely torqued out of position and it's very uncomfortable.
This mattress is even good for back sleeping, which is something I've not done in many years, primarily because my lower back wouldn't be properly supported and I'd wake up all kinds of sore. It also didn't work with my sleep apnea. Now, though, my back is very nicely supported, and with the CPAP I don't need to worry about the apnea as much.
It's hard to tell right now because of my ongoing knee issues has fired up my entire body, it seems like, but I'm thinking that this mattress is going to result in tons less morning stiffness and pain.
Ben, thanks so very much for the Sleep Innovations recommendation!