Like Robinson said in his podcast, the first thing he looks for in a new signing is pace - because you can coach the other parts of the game, but you can't coach speed.
He might not improve, but he was certainly worth the punt we took. If nothing else, his pace gives the opposition something to think about even when he's not doing anything. He certainly hasn't improved the way Hylton has, but Hylton had 150+ first team games under his belt before he joined so was less of a gamble.