I've been using Cowboy Magic and it was a miracle cure for matts on Rizzo. I have to keep him super clean though, more than 7 days without a bath and I start finding lots of matts, espically behind his ears and on his legs. I use both the shampoo and conditioner plus the leave in conditioner. With the leave in, I found that it really weighed his hair down so I mixed it with water (50/50) in a spray bottle and mist him before I brush him after his bath. If he gets a really bad matt I'll put the pure leave in on the matt and pull it apart by hand.
Lots of treats and praise to get them used to it