First thing that jumped to my mind was how good the viewfinder is, even against the very best on the market (Sony external viewfinder for the 5N). Yes, it's not as crisp and detailed as the Sony, but proudly holds its own. Considering the G1 is four years old, this says something.
In some ways, I prefer the colour from the Panasonic than the NEX-5N. It seems more vibrant and pleasing to look at. But when it comes to image quality, the NEX-5N is clearly the winner. Even at ISO 320, the G1 shows lots of noise, compared to the G1, thanks to the larger sensor and better on-chip noise reduction of the NEX-5N. The G1 reminds me of the original Canon 1Ds, where low ISO quality is superb, but anything above ISO 320, it gets very noisy.
The G1 is still a very capable camera. Certainly it's no worse than when it was introduced four years ago. We tend to want the latest and greatest, and forgetting that older equipment can still make beautiful images.
Lunch with the birds - Panasonic G1 & Wollensak Cine Raptar one inch f1.9. Click for larger.
Pink Dahlia - Panasonic G1 & Wollensak Cine Raptar one inch f1.9 @ f1.9. Click for larger.
Leaves - G1 & Wollensak Raptar two inch f1.5.