PSN vs XBL which is better?

[Reasonable]

I'll say the same.  PSN is free which is definately preferable to paying, however XBL does offer some additional elements and a better (more consistent) interface and experience around online gameplay.

Outside of that stores, etc. are more or less the same and vary by region.

So, on balance, the same for the most part.  Each as some pros/cons.