Regarding the 5.0.2 hang (partly repeating an earlier post): Trashing, restarting, and reinstalling 5.0.2 didn't solve the problem for me. Being somewhat lazy, I didn't yet try the second solution at which involves using AppTrap.
Instead, after force-quitting 5.0.2, I located version 5.0.1 in the Trash (which I lazily hadn't emptied yet), put it in a subfolder within Applications, and launched it. That works fine. No need to locate and revert to anything earlier; no need to re-sync all my notes either. Users who are quick to get rid of earlier versions won't be able to do this, unless the Evernote website contains some hidden page containing earlier-version downloads.
If anyone on the Evernote for Mac team needs it, I can fire up v5.0.2, wait for hang (which is pretty immediate), force-quit it, copy the crash log info into a text file, and post that. At least I assume I can, since I see that someone else has attached a log file to a post.