This position will give you great strength of vibrato and bends. Some people also use the thumb to actually fret the low E string (Hendrix, Vaughan). I personally don't do that.. don't have the fingers length for it lol
The only problem with this position that I personally find is that it is limiting when doing legato of sweeps but you won't have the worry about that for now. Just remember that as you move up the neck you'll sometimes want to go back to the thumb behind the neck.