Judging by the most recent Star poll, Smitherman's numbers look pretty good. Ford really only has a prospect of drawing votes from Rossi supporters, who are a small group, and even then are probably backing Rossi because they are allergic to Ford. GS, by contrast, could easily draw support from all three of Thomson, Pantalone, and Rossi, though much will depend on whether and when any of them drop out. I think it is also safe to assume that undecideds won't break in a big way for Ford. If you're passionate enough to believe a guy like him would be an improvement, odds are you have already made up your mind.
Additionally, I think it is important to consider that the old Red Tory/Blue Grit machine, which still counts for a lot in Toronto, is completely appalled by Ford. These were the people who, to some extent, delivered Lastman and, in his second election, Miller. Partisan lines are pretty fuzzy in municipal politics and that crowd will likely back GS in a big way. There's also the not-insignificant issue that RF is not, exactly, a great candidate except as a sort of template for 'suburban rage'--I find it very hard to believe that his long and well-documented record (criminal and otherwise) won't get a lot of folks asking harder questions. Similarly as the debate becomes more one to one with he and GS the flimsiness of so many of his ideas and claims will be more obvious, in contrast to someone with a substantial resume of accomplishment and reasonable ideas.
All that said, progressive Toronto should not by any stretch underestimate the Ford threat. He has obviously tapped into a sense of frustration that is bigger than municipal politics, and in turnout-sensitive municipal contests such a passionate base is a huge asset. But as the performance of a notional Miller run in that Post poll demonstrates the progressive bloc in Toronto is very large. We didn't turn into Alabama overnight, and the candidate that finds a way to acknowledge concerns about 'waste' within in the context of a positive, moderate, progressive and urbanist agenda will probably win easily. Incidentally, one of the things I would love to see Smitherman do is to attack the idea of 'waste' from the left, as in, 'we can't build a great city if we are wasting money,' rather than 'city council wastes some money, so let's turn back the clock to the fifties because they were so awesome.'
Adam Vaughan, who I think will make a great mayor one day, had an interesting interview in NOW recently that I encourage all to check out (sorry, tough to paste link on iPad). Basically he said that candidates who think they can win by complaining about the Miller era are dreaming, since the people who see that as the most important metric are going to go to Ford. The rest of us want to live in a city that is getting better and moving forward, and the candidate that presents a vision of the future that appeals the the great middle is going to find a lot of success. I think I agree.
In any case, I am trying to remember that the only people paying attention right now are journalists and folks who are passionate on either side. We really can't conclude much of anything yet.
An edditional thought edited in: I have been surprised by the extent to which even high-information voters of my acquaintance don't really know anything about Ford. To city hall-watchers his stunts and flaws are well-known, but the vast majority of people pay very little attention to the ins and outs of the clamshell. That makes me suspect much of his current poll support is down to name recognition, which has of course been aided immeasurably by the exploding-heads routine that is getting played out among, say, Star columnists. I am really hoping that one of these days we will start seeing election headlines that don't start with his name.