Nah, he's not shite. He just has a heart the size of a pea, disappears when the going gets tough, hardly ever creates chances for others, is too slow to play on the wing and has a dodgy knee. He's a good goalscorer, although his record is a lot less impressive when you exclude the penalties.
More seriously, I think he's at his best when he's basically playing as a second striker. He struggles to influence the game on the wing (which is where I think Rangers intend to play him) and that's partly why I think he'll fail. He'll end up at a Barnsley/Rotherham type club or back at Tynecastle in a couple of years.