I bought a Voiglander 28mm finder (from Camerquest--good personal service from Mr. Gandy) about 6 weeks ago before leaving for a trip to central Europe. Before the trip, I would have been among those users who said that I need some viewfinder and was uncomfortable holding the camera out to compose on the 3" LCD on the back of the camera.
I was a little disconcerted at first by the fact that the image within the frame lines of the finder was only a good approximation of what was actually captured, but it was someting I eventually accepted and found the finder to be quite useful. The viewfinder seems well built, looks great on the camera, is clear and bright, and has easy to see frame lines. In my opinion, using a finder on the GR has a few significant downsides. First, with the vf on, I can't easily slip the otherwise pocketable GR into my pant pocket or a small jacket pocket. As you know, one of the great joys of the GR is to have available a tiny camera capable of taking high quality images which you can easily carry around without something hanging over your neck or shoulder. Second, although it fit snuggly on the external flash mount, I discovered that when shoving the camera into a tight pocket with the finder on it could come loose if I was not careful (there is no lock on this finder, although there may be one on other finders). So, the finder became a little piece of equipment (small and light, but relatively valuable) to carry around separately from the camera and worry about losing, damaging, dropping, etc., and I found towards the end of my trip that I left it off the camera more often than not. The lcd screen on the GR is excellent and I never had a problem with visability, although during my trip it was typically overcast and not bright sun on the screen.
My advice to anyone who just bought the camera is that the GR is an excellent, highly pocketable imaging device and using attachments with it that adversely affect its portability is a negative and you should first try using it for a few weeks without a finder before considering buying one.
