Sure there are much more powerful chess-analysis software available (ChessBase's DEEP FRITZ comes to mind), yet they are either much more expensive or sport features only professionals (or at least truly advanced players) would know how to use.
Not to be outdone at the gate, CHESSMASTER-11 features an exceptionally good teaching tool as well a human-simulation engine which is adaptable to various personalities and is now even multi-core and 64bit-compatible. For any chess-player ranked below 1400, this is the most recommended series.
True, compared to CM-10, this edition is not that different - with the exception of some visuals and animated board options. I could not see a reason to upgrade if one already owns CM-10
My advice: wait for Boxing Day sales - you will be able to pick this up for a song.