Actually, I am pretty horrified, in that the worst problems (IMO) from CM10th are still present in CM11 (if not worse!).
1) The Mentor Lines window regularly drawing poorly (with one-half a line below the bottom of the window) and getting stuck if you take back a move when analyzing a game. The drawing problem is also present in the Thinking Lines window. 
2) How long you have to wait when launching the program before you can actually start playing a simple game of chess. I have a fast machine, and it takes three mouse clicks (once the app starts up) and 45-60 seconds before you can make a move. Chessmaster 9000 (my favorite version, of course 

) takes less than 10 seconds. 
3) The new tutorials are very badly scripted. There are many cases in which Josh Waitzkin asks you "what would you play here", and then the program won't let you make a move, but instead goes straight on to Josh's explanation of the best move. There are many other very bad errors that are easily caught. True, there were many MINOR tutorial errors in CM9000, but none that were this obviously bad such that they actually reduce the quality and usefulness of the content. 
4) I appreciate the ability for the new engine to use multiple CPUs or cores, but if I enable that setting (thankfully, it's off by default) there are many times in which the program (and my entire computer) will completely hang for 10-30 seconds before becoming responsive again. 
The new content from IM Josh Waitzkin and GM Larry Christiansen is excellent, and is probably worth the price of admission by itself. But if I want to analyze a game or just play chess, I use CM9000. Once I'm done with the new content, I'll never launch CM GM again (just like I did with CM 10th Edition).
jm