I've just upgraded a big problem CCC site to 23 and they seem very happy now, especially with the CCC side of things, mainly because of the Delta Server .35.
I spoke to Tier3 the other day and they are very very happy with this build of Delta Server - and basically said if the customer is not happy with some of the data, it is probably more a case that they do not understand the data being reported. Hopefully these CCC sites will now be sorted!