AF speed and accuracy: Nikon 1 or Canon G1X
I had the G12 (actually still do but I now use the Nikon V1).
I liked the canon, though the use of the flash in aperture mode resulted in blown highlights. Running in auto mode didn't produce this, but I couldn't shoot in RAW in full auto for some reason. [ mini rant]
The G1X is larger then the G12, I'm not sure if you're really gaining anything in portability being a large P&S.
The advantage I think the V1 has is the speed, and size. The ability to change the lens is also a huge plus.