I've seen a lot of him and Send has got him spot on although that's not having a go at him.
He's very, very good at headers, an excellent tackler and he also hits a good ball, freekicks, pens etc so his distribution can certainly be worked on and should get better as he gets more comfortable at this level. He is a top class defender and I remember the Everton youth side playing Blackburn when him and Phil Jones (then centre half) where on the same pitch and the program had an article about Duffy being the best defender in the country for his age.
Duffy's very good, ideal for English football and should be in our team now. He reminds me a lot of Tony Adams in how he plays.
Just imagine if he'd made the mistakes Heitinga has lately, Moyes would of finished his career.