> What are some real world apps using CRDTs that have really good experiences?

Google Wave and Google Doc's use CRDTs.

There's a fun blog post or two on how an academic paper completely botched it's benchmarks on the underlying algorithms by putting together a piss-poor implementation of Google Wave's algorithm and proceeding to claim the algorithm itself sucked even though the piss-poor implementation was such a mess it outperformed everything from every angle..