I think its a toss up really, because cosina has designed the Bessa series with so many differences and incremental features, it really makes it easy to objectively look at the entire lineup and decide which one best suits your needs. The R3M/A and the R4M/A pretty much cover everything you could need in a rangefinder, and one of these 4 bodies will likely best suit your needs. I personally chose the R3A because I mostly use ‘normal’ focal length lenses i.e.: 40, 50mm. so the 1.0x viewfinder is the most amazing thing. ever. and because I wanted the convince of AE, the ‘A’ version was where it was at. but I could have easily chose the M version if I had decided that mechanical operation was a priority. if I used wide lenses the R4 would have been a no brainer, and again, mechanical operation (read: battery dependency) or not would have swayed my choice for either the A or the M. the Bessa’s are really extremely well thought out tools, and you have to give credit where its due, because not even the M6 or M7 can really touch the Bessa R3/4 series in a lot of ways. my only gripe is really the chosen building materials to save costs. but then again, if it were built more like a tank it would probably cost considerably more.