I have bought a P7100 in the last month or so and absolutely love it. I had previously used Pentax DSLR (and various P&S) and then a couple of years ago moved to a Panasonic LX3 which I love. The LX3 is a great camera but lacks range. The P7100 is great and the lens is super sharp to 200mm wide open although a bit bigger.
I looked at M43, Nikon V1, the Fuji X100 and even the new Canon G1X. I was always happy with the IQ from my LX3 so the P7100 only had to equal that and it beat the others on features. ( I am over changing lens and cleaning sensors). Anyway the IQ of the P7100 is equal or better than the LX3 so I'm very happy with the decision.
I've been shooting it wide open at the suggestion of other posters and the pics are fine. Have added a polarizer and adapter for not too many $ and that added to the 3 stop ND filter and the flip out screen (good for a small tripod) make it a good lightweight landscape camera too.
Great combo with the LX3 I go from 21mm @f2 to 200mm @f5.6 in 2 small lightwight serious compact cameras - better than carrying lenses anyday.
a few snaps