I can't say much about Citus, but cockroachdb mostly works as advertised. Plus it's getting better with every release, which come pretty frequently. Support (forums/slack) is also unimaginably helpful and friendly.

There's at least 2 big caveats though:

1. Although they are very transparent about limitations / PG compatibility issues, you'll almost certainly run into things you weren't expecting (because some of the limitations are only documented as bugs in github issues, which you probably won't go through every single one of before you start). Examples:

a. No partial indexes (which can be a pain if you had a unique partial index, solution add a nullable column to the unique index) - but there's clearly work being done on this as we speak

b. Index isn't used with now() (solution, pass it as a parameter)

c. No way to tell if an upsert did an insert or update (like using xmax in postgres)

d. More obviously: no full text search or geo

2. Backup options for the community edition is limited (which I think is a generous way to describe it). If you're used to (free) Barman, even their enterprise backup capabilities are poor.

For any serious work, I'd recommend you not use the community edition until #2 improves.