"Go further out, and a Finch ROW would save 50%. That figure would be even higher if the TTC brought in the honour system."
Err...not on Finch East. That would make it noticeably faster than a car, probably faster than a subway even. Finch West I shouldn't comment on because I don't ride it enough.
edit - just noticed I'm comparing a streetcar in a ROW to a bus in mixed traffic; you're probably thinking of a streetcar in a ROW vs a streetcar in mixed traffic...but they wouldn't put one of those on Finch, anyway.
I can see ROWs conceivably working well on Eglinton East, Don Mills, Kingston, etc. Streets like Kipling and Jane seem to be good candidates but they narrow considerably towards Bloor...although if St. Clair can be narrowed and everything works out fine, maybe the same could be true for similar roads.
more edits:
"I really think that reliability on ALL TTC routes, not just Spadina, is a major issue."
Most, not all. I can probably count on one hand the number of times my local bus route has ever been noticeably off-schedule going southbound, and I've taken it perhaps thousands of times. At least half the time, I can time my arrival at the bus stop and the bus' arrival to within one minute...going northbound is a different matter entirely, though, because I can't time my arrival at stations via subway. Of course, suburban bus routes like this are the exception, not the rule, but I have no continuing complaints with any of the other bus routes I take on a regular basis (except the Steeles night bus >: ). The TTC manages to offer reliable service on some routes without even trying, but on other routes its service manages to perpetually suck.