Lee's good, but he's been playing with a better team, and players that helps those numbers a bit. He's also on the down side of his prime.
Where Love is entering his prime, and has played with a crappier team, which can either be better for your numbers, or hurt your numbers, because teams can guard you easier, and your asked to do more.
It's hard to say who is 100% better. I'd give the edge to Love because of his age, and how bad his teams have been.
I would have really like Lee when KG was here, I think he would have excelled here.