Well, I like AU Charles. He's got a well defined background that makes him different from OU Charles.

Generally though, I don't have the same problem with any of the AUs, because the fact that they're AU means that deviations in their personality and behavior from their canon variants is expected. In an AU I mostly look to see whether their behavior is consistent, and for AU Charles it definitely is. I will always prefer a well-developed and consistent AU to an OOC OU.