I spent several hours yesterday out with my NEX-7. I'm still getting used to it, but yesterday (after a couple of weeks of shooting) was the first time when it started to click with me.
I choose the "universal back" option in the poll, but the -7 is more than that. Great with legacy glass via an adapter, but the 18-200mm Sony lens is quite good.
I could now travel with my M9, 3-4 M-mount lenses, the NEX-7 and the 18-200, and have a very small kit with incredible range and quality.
Just my 2 cents worth.