The pros:
- unique viewfinder
- compact
- light
- good AE
- exposure compensation button available
- easy to load
- film cassette visible in rear window
- shutter goes dow to 1/2000th
the cons:
- VF close to lens mount, hence heavy vignetting unless you use pancake lenses
- the lever on the rewind crank can get loose and block the film advance if you shoot vertically
- the camera on a strap exhibits a nasty backward tilt, unless you put a heavy and long lens on - which you most likely will not, as it would block the finder
- the shutter is a bit louder than Leica or ZI
This camera excels with the 28 frames, 25mm are pretty good if you do not wear glasses, 21mm frames are a stretch, but it is the only game in town without the outside finder. The 35mm frames are marginally usable, the 50mm frames are for emergency only.
For the question of auto exposure or not, I recommend the R4A, as you can always turn it into a manual setting, but not vice versa. If in doubt, you can compensate quickly with the button, or by turning the shutter speed dial to compensate for the entire roll or a series of shots.
For me, this is the body most often used with the 21/4.5 C Biogon.