Ok, let me put my 2c.
1) My overall favourite film camera is the Nikon F6 (but it isn't allowed in this specific thread) - If I had to choose only one camera for my life, it would be F6 for sure.
2) My favourite manual focus camera - especially for portraits - is for sure the R8/R9 - Keep in mind I also have a FM3A and time ago I wrote about the differences about them. Not in terms of build quality in itself, rather about the viewfinder. Despite the FM3A's micro-split prisms collar and focusing area is (or seems to be) bigger (!) than R8 ( I could look at them side by side ), R8 has a couple of clear advantages over the FM3A at least in term of usability. First, the central focusing area is much better (i.e. it's easier to understand what's in focus and what is not) and second I find the right side exposure times much smarter than the left-side FM3a.
In fact, while the right side is always in the most lighted part of the frame, especially for a portrait, the FM3A falls in the darkest AND, not to rely on batteries, has no lighted exposure times as R8 has, i.e. you may not understand at which time you're working.
There's another plus which I like a lot compared to many others manual cameras, FM3A included (notice I don't have yet any R8/R9 but I'll get it asap): spot metering. The bread and butter lens for that camera is the Summicron 90 F/2 while I'm not that much fan of the faster and heavier 80 F/1.4. I also had the opportunity to look through a Contax T2 viewfinder but I didn't like it as much as the Leica. No idea for RTS III which should be a great camera indeed - actually for what I saw, it looks even harder to find than used R8's. R9 is even harder to find.
3) Another AF camera I could choose? F100 or F80, one for performances - F100 af still equals or overcomes many digital cameras autofocus systems, lenses looks driven as dragsters. F80 is cheap but has a fill-in flash and a few nice features that may result handy.
Bottom line, if you could get a R8/R9 I tend to think you would be perfectly happy if you like manual focusing AND your favourite focal lenghts are 50 / 90 mm Also the 35-70 F/4 often disregarded because "slow" it's a truly great lens, optically speaking, and a very good walkaround to pair with a 50 F/2 Summicron and 90 F/2.