I can't speak of which one has more reliable hardware as I've had both a ps3 and a 360 that bit the dust. I only beat one game on the 360 before rrod; my ps3 died (ylod) in less than ten minutes of turning it on for the first time. my second ps3 and 360 work perfectly fine.
pros:
Xbox 360:
a far better controller
better online
multi-platform games r generally better
Playstation 3:
better exclusives for the most part
free online
pretty much works with any laptop hdd
cons:
Xbox 360
ridiculously overpriced hdds (a $60 hdd in a $60 shell?)
incessant nightmares of rrod for many gamers including myself
microsoft points r a joke (being forced to buy more points than u need--wtf?)
paying for online
Playstation 3:
xmb just feels clunky and disorganized (the options section makes absolutely no sense)
no alphabetizing of psn
downloads? (come on! how could they overlook the most basic sorting system after five years?)
the removal of other os is forced on u just to play new games or connect to psn
the controller is too small and u can't remove the battery
although the exclusives r better, there is also a tremendous amount of crap in that department as well.