Well, I've used Dans alot and it ALWAYS brings improvements but you need to be able to adjust the training to suit the player. If you have a youngster who is very poor physically you need to tweak that until he's decent then set it to how it was.
Dans is great, it covers all the positions and even has a few extra ones like "target man", it will get you results but as I said before you need to be able to tweak to your players needs.
Once my laptop is back I will be able to show you some of the improvements my players have made.