They both have problems. Which is worse? Currently...Sony. In a few months, when this has all died down? Microsoft will still be left with most of it's issues.
Xbox shits all over free members and has RROD. (I can't even send messages now as a Free member.) Plus, it just freezes a lot in general. And it can only store a few game patches at once, meaning frequent patch downloads if you cycle between a lot of MP games, like me. For some fucked up reason. And if you are offline, a large number of the XBLA games won't work. While my offline PS3 can play all of it's downloaded titles just fine.
Sony has the Yellow Light of Death, far less prevalent, but still an issue. And this whole shitstorm going on now. And the forced installed for DOWNLOADED games, basically doubling the time to play content you DL. Installed a 6 GB game that you downloaded takes...basically a half hour.