Nikon V1 or Panasonic G3?
Which one to get
I have a V1 so that is what I would obviously recommend.
But I also have Nikon DSLRs and I can share lenses as well due to the Nikon FT-1 adapter. For example, I can use my Nikon AF-S 70-300mm f/4.5~5.6 on the V1 for an simulated focal length of 810mm, retaining full control over the lens (autofocus, vibration reduction, PSAM exposure, etc). Thing is - Nikon designed the FT-1 adapter for the V1, and it works properly.
The original price of the V1 ($899) was ridiculously expensive. I would not buy one at that price. I waited until Dec 2012 when they went on sale for $299. For that price, they are a bargain.
Thing is, the Nikon V1 is just fun to use. I still go to my DSLRs for serious photography, but if I just want to have fun, I use the V1.
According to DxOMark tests between the Panasonic G3 and Nikon V1, the Panasonic beats the V1 for low-light, but the Nikon beats the Panasonic in Dynamic Range and Color Depth - which is pretty impressive considering the V1 has a bit smaller sensor.
And the Nikon 1 system has perhaps the best autofocusing system ever - even better than pro DSLRs (up to 135 focus points - phase and contrast detect hybrid).
http://www.dxomark.com/.../Panasonic
However, you can read specs all day long. Why not visit a camera shop and look at both of them and see which you like the best.