I have to be honest and say I learned more in the first 3 years of playing than I have in the last 27. :(
But I agree with Blue, it's just a form of notation specific to the guitar, there's nothing wrong with that. You still have to use your ear to get things right - I doubt anyone could play a piece of music they'd never heard just from a piece of tab.
I don't have any natural ability to just pick something up by ear - I suppose I can pick out a melody easily enough, but I can't necessarily get it in the right register or even the right key, and I haven't a hope of identifying the chords. I'm always amazed by these guys who can apparently learn songs in no time.
I must say, though, if I do figure something out by ear, I can play it better, I suppose because I've worked out a fingering that's natural to me. When I try to use tab the fingerings often feel very awkward (and I give up pretty damn quick).