It's slow. The hysteretic control makes it unpredictable in terms of frequency, hard to filter, and in some cases quite noisy. The current-limiting behavior is overly simplistic for many applications and wasteful with its huge 1V threshold. Current-limiting is slow, meaning it doesn't do much against things like core saturation, and the output transistors are fragile.
The cheapness is a benefit, of course, and I'm not above using one where its many drawbacks aren't a detriment.