http://news.ycombinator.com/item?id=3974403 (reply threshold is high enough for me to post now)
Re:Migrating From MongoDB To Riak At Bump
by whatusername on Tuesday May 15, 2012 @10:01AM
(#3976570)
I wonder if NonStop SQL ( http://en.wikipedia.org/wiki/NonStop_SQL ) might count..
How often did you manage to spectacularly fail PostgreSQL to qualify it an 'operational nightmare'?