Tough for HA, default Postgres has everything you need to get started.

The one thing that's missing is automated failover, but personally, I wouldn't do that with a database because from experience, from all the issues that would cause an automated failover, only a very small part would actually be solved by such action, whereas most of them would probably be made a lot worse.

Especially considering that undoing a failover is very costly (in terms of time, not necessarily money) until we get 9.4 where failing back to the original master won't need a full resync.

As much as I dislike lots about Oracle, the Oracle DB RAC cluster sets the bar pretty high, imho. Multi-master with automated failover that just works.

I've been working on an automated failover framework based on Zookeeper and ZFS for some time now. Whilst we use it in production, it's been hampered by bugs we keep hitting in the PG replication layer. Coupled with the problem that the PG WAL includes checkpoint data in addition to transaction logs, it makes it quite difficult to get right and make the system completely hands off.

Sure, didn't mean to imply that I thought this was a big advancement there (haven't looked at the options deep enough to tell, this included), just that the two concerns are different and YAGNI may apply to scale but not HA (though it can certainly apply to HA as well).