We ate at CM about 4 years ago - I was SO excited to go, since I had heard it was a "must do". We waited over an hour (with and ADR). For that reason alone, we have never been back.
We do love Disney's character breakfasts....we do one almost daily. My opinion is that there are so many other GREAT experiences for a character breakfast, that we don't waste our time of going to CM's.
Also, in case some people may not know, you can made a ADR for a character breatkfast IN a park prior to the park opening (say Crystal Palace at MK - for an 8 am breakfast - with a 9 am park opening)... and get to walk down Main Street almost by yourself!!! It's a GREAT photo opportunity as well! (and you can eat AND be IN the park for opening!!)

