An interesting addition to the 4th edition game. I liked many of the powers and did not feel they were too overpowered or underpowered. I also liked the different flavor they gave to the Warlock class.
3rd party publishers of D&D4 material are at a severe disadvantage. They can't add their material to the DDi and that makes them less attractive. But if you can get past that this is a very good class build and one I plan on using in my games.
[4 of 5 Stars!]