I recently acquired a GA645 (60mm F/4) and I'm very happy with it. It's light weight (lighter than my 35mm SLR + a zoom) and you can carry it everywhere. That's very important to me.
Even for 60mm at smaller aperture, the DOF is shallow and I need to be extra careful with it. And with smaller aperture to gain DOF, the shutter speed drops and thus I would say, w/o flash, it's a day light camera (handheld) or you need a tripod.
And the lens....is *deadly* sharp, as many people have said.
Metering is quite accurate for shooting slides. Autofocus is fine; I think half of the time I use zone focus or hyperfocus. The camera is really a joy to use.