Just thought I'd chip in with my own answers to these questions, and perhaps give anyone else a chance to respond who hasn't already done so (I'd have thought there were more than 50 people active in these forums who have played TOC...):
1) Approximately 30 times the normal way, plus once backward.
2) I think the Old Course is in a league of its own. There are (a few) other courses I'd rather play, but there isn't another course you can compare TOC to for strategic depth and replayability. I agree with Tom Doak's comment - "once you have a map of it in your head," it becomes a strategic masterpiece that *any* golfer allowed on to it (i.e. 24 handicap or better) can appreciate. The problem is that very few people, apart from its residents, are ever in St. Andrews long enough or frequently enough to acquire that knowledge. I don't think you can hold this fact against the course itself - surely the greatest compliment to a course is to say that you'd be happy playing it every day - but it is true that until you get to play it at least 10 times (a conservative estimate, that), you can savor TOC for its historical and atmospheric greatness, but you can't really understand its architectural greatness. In my humble opinion, of course.
(That said, I believe the answers of everyone heretofore back me up - the people who haven't tended to like TOC are the ones who have played it a few times but less than 10 times, i.e. enough for the initial buzz of the history and the St. Andrews atmosphere to have worn off but not enough to get beyond the knowledge gap.)
3) Much higher. I appreciated TOC for its history before I played it, but having been so fortunate as to get to spend a year in St. Andrews, I feel blessed to have gotten to know TOC so intimately. I'd very happily go back for another year, or ten...
Cheers,
Darren