The best users are the 35S and 35SE - both have the 40mm f2.8 Sonnar with HFT coating.
The 35 and 35T, 35TE have the 40mm f3.5 Tessar lenses.
There was a limited run of 35S models with S-xenars.
Check out this site for more info.
http://johnlind.tripod.com/rollei/rolleiframe.html