I don't see the user experience on Twitter being on a par with neither StatusNet nor any of the third-party clients out there.
Third-party clients have, however, not implemented StatusNet support despite the fact SN has a Twitter-compatible API. _That_ is something I don't understand why.
OStatus is just about as short as it can be on its own. "The 4 other specs" _together_ aren't much longer than what is necessary _anyway_ for implementing the necessary aspects of a federated social network.
And as all of the protocols necessary already exist and are quite well-established, there are already parsing tools available for anyone to use freely. So development is really easy to get into when it comes to OStatus.
Using something that already exists is in this case much better than reinventing the wheel and rediscovering all implementation issues that have already been taken care of with protocols like XMPP or OStatus.
Third-party clients have, however, not implemented StatusNet support despite the fact SN has a Twitter-compatible API. _That_ is something I don't understand why.