Jeff Green might not carry your team, but he also won't actively kill it the way Smith will. If you need a go-to scorer, you don't want Josh Smith. I think Green knows he's not a #1 guy and won't force himself to be something he is not. Smith thinks he can be "the man" and will shoot in an attempt to prove it. The book on defending Smith has been to let him take open jumpers in the first quarter so that he keeps taking contested jumpers in the fourth quarter.
Josh Smith played one season where he only took seven threes, rumored to be because of a bet. That was the one season when he was truly effective and the only time the Hawks won 50+ games while he was there. The next season, he was back to his chucking ways.
He can be a good player, but he insists on taking enough bad shots to outweigh all the good things he does on the court. If he were a Celtic, he'd be like a more frustrating Antoine Walker.
I can see Jeff Green being a key rotation player on a contender. I can see Josh Smith sabotaging a team that has the talent to be a contender.
Bottom line: DO NOT WANT.