I have the GA645Wi, it's great, auto focus works well, image quality very good. The manual focus ergonomics is not great but it works, no range finder so zone focus only, apart from that the ergonomics are quite good, nice grip. It's pretty light ~900gr and with the retractable lens it fits easily in many small bags so it's great for travel, I don't think it stayed home on any of my trips since I got it!
Tripod landscape shooting is a bit bothersome because of the default portrait orientation. I guess one could get a bracket to make it easier. The lenses are not very fast, F/4, so for low light photography it is not the best, although with the leaf shutter it is possible to handhold at low shutter speeds.
The non-Zi models should't have the lcd/ribbon cable problem.