Little new content since 10th edition; but for $20 it is worthwhile for those interested in new Academy material.
The Bad: Online play does not support matches with Chessmaster 10th edition, very few online players compared to http://www.zone.com, many people experience glitches (I haven't), not much new material added since last version
I can understand how frustrating it is to have a glitchy game, which seems to be a problem many people are having with Chessmaster: Grandmaster Edition.
I just bought this program two weeks ago (June 2008) and downloaded the patch; I haven't had any problems so far. I run this on Windows XP with an NVidia GeForce 6800 video card.
I bought this game because I like the academy lessons with Josh Waitzkin. The only new material for Grandmaster Edition is the "Art of Learning." This new section has 14 more annotated games along with some introductions on chess concepts. This is primarily why I bought this game considering I already own Chessmaster 10th edition.
If you like the Chessmaster games, you will most likely enjoy this one. Like I said, I haven't experienced any glitches, so I can't speak for people who find this game very glitchy. Peppe212 said in his review that this game takes advantage of HT/multi processors.
There is not much reason to upgrade if you already own Chessmaster 10th edition, especially if you are not interested in the academy portion of the game. This game has nice graphics, but I personally don't care about 3D visuals because I always use 2D game pieces.
If you are sitting on the fence and don't know whether to buy this game, consider that since it is only $20 it will not set you back that much to buy it. If you only want to play chess with human opponents, then save your money and visit www.zone.com for free online chess.
I would like to see more annotated games in future editions of Chessmaster. They need to add more content to the academy with commentary from grandmasters.