That's the thing that bothers me. I shot today with teh Voigtlander 35mm finder on the GF1 with 20 f/1.7--a good fit. But---getting AF if you shoot wide open is more difficult--how do you know you nailed it?? That's more difficult. I really couldn't tell with the LCD, of course I 'got' focus with a low audible beep--but was it the one I wanted?? I'll know when I load them up to LR in a minute LOL. If I'm stopped down more I can use mulit focus points and be careful of composition and be reasonably sure I will get it--and I can shoot more wide open and 'guesstimate' the center AF button and place it where I want, get focus and recompose--but--I'd just rather have the EVF. The finder is big, bright--fine for many situations, but I like shooting more wide open and that's more iffy--at least for me. I'd be glad to hear of anyone else's suggestions for using the finder in those circumstances. Probably I just have not thought of the better way--I'm a longtime OVF shooter, so only used the finder on my G9 and now on the GF1.
BTW--I was carrying both the G1 and GF1 so was fine--but wanted to shoot with the GF1 just for the experience with the finder (or using the LCD in those situations where I could).
Ah, you posted just before me so I can answer about no visual confirmation. You have to remember that these finders have no connection to the camera in any way-they are slipped into the hot shoe and you use the bright lines for composition only. The accessory EVF of course has visual confirmation. You may be confused by the 2 finders. The OP is talking about an external VF that has bright lines to aid in composition and parallax error lines to help in that for closer than 10 feet shooting and not the EVF that can be added to the GF1--which will work just like the EVF on the G1 but with less resolution, size.
Diane