If you read comments on articles in the local press in the North East (there was an article promoted via social media yesterday from the Boro Gazette which featured a bit about AC), the overriding opinion was that he is one of the worst strikers they've ever had - both in terms of attitude and ability (both on and off the field).
I don't really understand criticism of his on-field attitude. I think the bloke is a complete bellend with an attitude (or at least immaturity) problem generally, but on the field he always looked like he was trying his heart out to me, he is just nowhere near good enough for the Premier League yet. The club made a big mistake with his pathway to the first team, they should have insisted on the Ben White approach. I think if he'd have played any other position than a striker, they would have done. I doubt they'll make that mistake again.
I'd be amazed if we don't ship him out on a permanent deal this Summer. Assuming someone will take him of course.