OS is solid but I'm noticing alot more application crashes. The biggest culprit seems to be Safari. It goes down at least 2 times a day. Usually in response to sites with complex poorly written EMCAScript. Or multiple Flash Movies. Have also noticed less stability in JAVA apps particularly Zend Studio and JBuilder. But that's more like once every couple of days.
Install over writes ( and fails to back up ) under the hood configs. Overwrote both my /etc/hosts and /etc/http/httpd.conf files. Not a big deal but it should at least make a back up first. ( fortunately I do this anyway)
Other than that I LOVE THIS OS!