I think the "slowness" comment was about the time taken to set up for a new subject rather than frame-rate once the appropriate shutter-speed, aperture and focussing distance have been selected.
It's a fair point. The handling is very quirky and people tend to either love or hate the things. As stated, I'm in the "love" camp (That sounds so much kinkier than I intended! Fun though! ), but I can understand people who aren't.
The destination is important, but so is the journey
I love my 35T with it's Tessar lens, and actually prefer the rendition and character of the Tessar for B&W street work vs. my Contax T2 with it's Sonnar lens. The Tessar is VERY sharp, assuming it's properly in sync and adjusted, I hated it until I had a CLA and found it was WAY off. Now I think it's right up there in sharpness to any other lens I own.
Fantastic camera ... I have only just started using mine and I absolutely love it's quirkyness. Reasonable 400 film and a Rollei 35 and you can handle most situations with ease. The tessar lens on mine is excellent even though only f3.5
Kodachrome 64 ain't worth any effort to use. It's contrasty, not particularly sharp, has very limited latitude, and takes forever to get processed. Kodachrome II and Kodachrome 25 were worth fighting for, but no more...!