APC leaves a lot to be desired such as a basic way to turn it off via .htaccess. I don’t need things I rarely use and get no traffic to (such as phpmyadmin or other tools that I only use) to be cached, ever. xCache easily gives you the ability to exclude these via a php flag in an .htaccess file.
I’m not sure what you mean by stability either. It’s just as stable as APC.
