Career-wise he's slightly better than 1 in 3 (126 in 373 in all games).
I haven't seen that much of him recently, so have no opinion on his likely value to us. It does look like he's had spells of goals including 23 in 43 at Coventry. If we could get that out of him it would be a result. If we got his Dundee Utd form, not so much.
As we've seen, a change of scenery can sometimes be the catalyst for a player, and maybe GA has a plan on how to get the best out of him.