I have a Konica Minolta G600. I think its pretty decent, but I want a camera with a more powerful zoom. I found the Panasonic TZ3, but reviews say the images are grainy for anything over an ISO of 200. I see they now have released the TZ4 and TZ5. Does anyone have experience with these yet? Are these new cameras better with the grainy images? And are there any big differences between the TZ4 and TZ5 other than megapixels?

I want to upgrade cameras for the zoom, but want to move up in image quality not down. I just want to make sure the Panasonic will be a good forward move. Any help is greatly appreciated!!!