I have used the G3 by itself for time lapse (manhatten during sunset) and it works well. I was then introduced to it's 100 shot limit (which is just silly) so I hooked it up to my laptop to take some shots of one of my plants (to see it's feeling towards sunlight at different times of day). Crazy? Maybe... But using the software with a laptop opens up an unlimited quantity of shots (limited by your HD)- although camera settings are a little more limited. I find that shooting at a high quality for time-lapse, then reducing and combining the files makes for some high-quality video indeed... As for as shooting times, I was able to shoot as close a 15 seconds apart with 3 second exposures. I didn't need to shoot any faster (might as well use a video camera then) and I'm not sure how the camera will stand up to a lot of shots and data transfer, but;
In short- the G3 works quite well for time-lapse work.