I finished BL today.
I don't have any strong feelings one way or the other regarding Jack Black, but I think he was pretty much perfect as Eddie. The rest of the cast are great as well, the voice work was top-notch overall. The game isn't the best looking ever from a technical standpoint but great art design gives the game a lot of charm and leaves it looking fantastic anyway.
The world is well designed, and I had a lot of fun just driving around the looking for things and doing the side missions when they came up. The dragon statues and other trinkets aren't as well catalogued as in Psychonauts, where tracking down what you were messing in each area was made easy by a handy list of what you had where, and I don't know if I'll go back to find every single thing I missed, but I enjoyed poking around while I was making my way through the game. The combat and action gameplay is kinda average, adequate but not really a lot more. The stage battles are great, infusing RTS elements to create a fast, strategic action game.
The pacing is just about right, perhaps falling slightly on the side of "too short". It doesn't wear out its welcome and leaves you satisfied, if wanting just a bit more.