Along with most of its features the Lumix G2 also inherits the G1's excellent performance, and even improves on it in some respects. It can start up and take a picture in about half a second, which is comfortably into DSLR territory, while its shot-to-shot time in JPEG single shot mode is approximately 0.8 seconds, while in Raw + JPEG mode it can shoot at the same rate but only for four frames. In continuous shooting mode it can maintain 2.5fps, which is actually slightly slower than the G1.
The G2 has the same contrast detection AF system as the G1, and it is still exceptionally quick and performs well in most lighting conditions. Shooting in very low light is helped by a good bright AF assist lamp with a range of approximately four metres.
Comparing the image quality results with the G1, there doesn't appear to have been any dramatic improvement. Noise control is still very good up to 400 ISO, but there is visible noise at 800 and a sudden drop-off in quality at 1600 ISO. The improved 6400 ISO maximum sensitivity is pretty poor and only for use in extreme circumstances.
Colour reproduction in JPEG mode and the Standard film type is a little over-saturated, but the dynamic range and level of fine detail are comparable with a 12MP DSLR. Unfortunately at this price level it has to compete with cameras that have 15 or 18 megapixel APS-C sensors, and even in Raw mode it struggles to keep up. Compare the test shots with those from comparably priced DSLRs such as the Nikon D5000 or the Canon EOS 500D and it's pretty obvious that the full-size cameras have a noticeable advantage in image quality.
One major highlight however is the new 14-42mm kit lens, which is a distinct improvement on the older 14-45mm lens sold with the Lumix G1. The new lens has superb corner-to-corner sharpness with no visible chromatic aberration or wide-angle distortion. If you're thinking of upgrading to a G2 it's probably worth trading in your old lens for this new one, it's that good.
The Panasonic Lumix G2 is only an incremental upgrade from the original G1, but most of the changes are for the better. The touch-screen is, as always, just a gimmick, but the video mode is good. Build quality, performance and image quality are all still of a very high standard, but you can get better results from a full-size DSLR of the same price.