I have two waiting-for-review updates that have been sitting in the queue for 9 days now. This seems much longer than my past experience of 2-4 days turn-around. I wonder if these delays are related to the corrupt updates issue.
How much they play around with the app seems to vary - I've had odd, hard-to-trigger bugs get my app rejected, even though they existed for several prior versions.
Each app submission/update costs Apple a fair amount of money to review.