I was looking at the Mini Cooper S, and may go in that direction at some point, but right now, I still wanted a little convertible. You know, the "fun in the sun" thing.
So far, I am very impressed with the little Pontiac. I had read that the turbo verion (GXP) did better for gas mileage than the non-turbo, and while I can't say what the non-tubro is doing for mileage, I can tell you that (with my driving style) I'm AVERAGING about 29+ miles per gallon. For comparison, I would probably be getting closer to 40 with the Mini. That is just a guess on my part, but I think it might be fairly accurate.
My plan is to probably keep and drive the Solstice for at least a year or two, then go into the Mini. Not sure because things can change, and things seem to keep changing, but that is my thinking right now.