We have two PS3s that is used not only as a gaming system, but is also our media center (We don't have cable, we stream everything through our PS3s). I'm setup to auto-sync on one, my son is setup for auto-sync on the other. I like to periodically sync the game saves between both PS3s as we don't know which one will be free to game on. (I don't like telling someone to quit playing or watching something because I need to sync something.)
Auto sync is nice and everything, but only if you have one PS3 and one account.
Also, I had a PS3 die not long ago.. It was a nightmare manually downloading ALL those locked game saves one by one (which was a lot).