My thoughts too. It seems logical to suggest that TDD would reduce the number of bugs in the product that's being tested, at least somewhat. However, the true question may be if the time spent writing those tests (longer that the time spent writing code?) is worth it when looking at the number of problems it prevented.

I believe the practicality of TDD depends on too many factors to make statements about it in general. Is your project well defined (good for TDD) or a cool little idea that changes and morphs every day or two (bad for TDD). Is it large scale and complex (good for TDD) or quite simple (TDD may be a waste of time here). There are more factors of course too.