I have not found a bug in 7B80, so ... Sure, there are applications that will need to be updated. No problem. This was like that with every release of Mac OS since I can remember, really. But OS-related bugs? Haven't seen any lately. And I believe that 7B85 is pretty bullet-proof stability-wise...
However, I find it strange that Apple would _not_ test Final Candidates with ADC members... Quite unusual... And they still have time to churn out a few more builds until the 10th, which would be the the 'Release to manufacturing'-day if the 24th should actually _be_ the release day.