Sumedh from Citus Data here. I'd love to hear what difficulties you ran into, or any feedback you may have on pg_shard. My email is in my profile if you want to drop me a note.

We are also actively working on making our products easier to use and would love to get more user input along that way.

Yes, we moved to galera cluster. Even with its random node shutdowns, from my second-hand impressions it's still better than dealing with the pgpool, slony, et al.