I have used all the medium format cameras pretty extensively. I currently use a Pentax67 with 4 lenses and I love it. I have always enjoyed the system but lately I seem to shoot everything with either the 67 or a 4x5. I highly recommend the Pentax. It is quick and easy to use and if you get one with mirror lock up, and use a cable release, there is no vibration problem. Another possible suggestion would be to go straight to 4x5 by getting a Speed Graphic. I use mine hand held. Using the rangefinder it is almost as fast as a medium format.