I agree that DL has its advantage like no need to load the disc, or won't be damage.
But you have to bring your console or download again the game (which can be very long) if you want to play at a friend's home, you cannot re-sell it, you cannot lend it (legally, since it could only be on 5 ps3 system that you own).
I don't talk about the size on the hard disk since you can upgrade it.