At least in Europe, SL35-Es are fairly common and 3 out of 5 were working properly (o.k. one had no BC function or working self-timer).
A beat-up one is probably actually a good sign: It worked properly for a long time (chances are that it'll continue to do so).
The Rolleinar 80-200s were made in at least 2 versions by at least 2 different manufacturers. I had one (don't remember which), which was quite decent.
Teles: Both Zeiss 85mm are wonderful. The 135mm have a great reputation (haven't used one). The 200mm is optically excellent, but the pre-HFT version is mechanically very delicate (diaphragm mechanism). The Rolleinar (Mamiya) 200mm is optically a touch behind the Zeiss, but still excellent and mechanically better.
The other Rolleinars tend to be quite- to very good, though usually not at the level of the equivalent Zeiss optics (when an equivalent exists!).
My "desert island" lens could well be the 35mm F/1.4, but in practice I rarely use it because of the size & weight of the beast.