Xcode 4's C++ support is actually pretty good. It supports most of the C++11 features. It still crashes on me pretty often but it's much better than it was.
In fact, C++ is just about the only reason I still use Xcode for actually writing code. My apps that don't need C++ are all written in AppCode.
However, AppCode's C++ support is also improving so it may not be that way for long.
