HI, I have a Rolleicord IV which has become probably my favorite camera out of several 35mm and medium format models that I own. It is very light and portable, and I really appreciate the medium format negative size for b&w. It had a very dark viewing screen when I purchased it. I improved it dramatically by replacing the original dark Rollei screen with an inexpensive Mamiya RB67 screen which is much brighter. I simply used a razor blade to trim the Mamiya screen to the correct size.
The only thing I miss with this camera is an in camera light meter. I would like to find a later model Rolleiflex for that reason. The lens on the Rolleicord is excellent, although I never shoot wide open to fully test it's capabilities.
Hope this helps.