Take the Rollei TLR and the old Mamiyas: you wound a knob at the side of the body, a natural movement, quick to do and easy on the wrist. Contrast that with the helical focussing system of other such cameras, where the lens itself has to be messed around with in an unnatural, twisted wrist manner. I think the difference in comfort also carries over into how comfortable/confident the eye becomes when the wrist is not at ease. It's all connected, as they say.
Having had both the Rollei TLR and then the 'blad straight after it, though I was able to focus both well, I do think I remember the Rollei as quicker. And without doubt, once you start to 'hunt' with focussing, it goes nuts very quickly - or at least, you do!
I agree completely with this, having also owned and used the Rollei TLRs and the 500 series 'Blads. The Rollei was a lovely thing to focus (well, lovely in a lot of other respects, too). Since I originally posted this thread, I have to say that I have improved my focus hit rate tremendously - from about 50% to nearer 80%. I have evolved a little 'trick' which seems to work for me, but I hesitate to suggest it because it may just be something to do with my particular eyesight / glasses / general ineptitude.