Early on I had some problems with the phone rebooting, but since the 1308 update it's been rock solid (even before the update it was pretty good, meaning maybe one random reboot a month). Haven't experienced much problems with apps at all, a few games that crash on occasion, but that does not seem to be directly related to the phone. Only 8 gb of internal storage means that you'll have problems installing games that take up a lot of space, like the batman or spiderman games.
Overall I'm pleased with the phone (been using it for 5+ months now).