I did update yesterday and was on Aperture for about 90 minutes, during which time it crashed once, but remained stable after the crash. As you say, nothing to be done unless you want to restore via a backup (but I'd done too many changes since my previous backup a week ago.)
Doubtless there'll be a fix if it causes too many problems. BTW, I'm still on Snow Leopard so it would be interesting to know if the same has happened to Lion users.
John