Both have had problems, the ps4 has more at the moment.
A lot of the xbox faults were software which was patched, I think it had to do with location faults. It wasn't loading due to thinking you had foreign discs.
The ps4 have had software and hardware problems, the hard drives were having problems pre release and yet they still released it.
In the end all of us who have bought a newer system are paying top dollar to be guinea pigs.
The thing I'm pretty pissed at is that it's stupidly hard to progress in games, the publishers have intentionally giving you less in game awards so you have to keep buying in game cash or points like in the cell phone game market. And that's without all the add ons which they stripe you up for.