I think we definitely want to move to the official client at some point. I have two relatively minor concerns at this point, though:
1. Despite being the official python implementation going forward, it's not as mature or production-tested as pyelasticsearch. Not a dealbreaker for merging into master, but it will require some time before our next release to shake everything out. I'd like to continue to beef up the ES tests, as well.
2. There's a small chicken/egg problem, since Honza doesn't want to release an update until we pull/test. But once we do, people won't simply be able to "pip install elasticsearch", since they'll need the master branch. If ES is planning on release 0.4.3 anyway, I think we should contact Honza, let him know the tests pass, and wait for the next release before pulling. It's one less hiccup.
Dan