[orthecreedence]

I've done a lot of research and testing with Riak (not had the pleasure of using it in production yet), and although some of the things that are easy in other DBs are backwards (like listing all records, for instance), I have a secret love affair with it. MongoDB claims to have simple scalability, but I've worked with it on a large project at Aol and found this to not be true at all. We basically had to implement our own sharding on top of it since its auto-sharding was so poor, and only needed to shard in the first place because of the global write lock. Riak, on the other hand, is an operations dream, and if you're a dev and ops guy in one (like me) I stay up at night thinking about using it for every project.

That said, a lot of people have started to use Riak for a general purpose tool. There are some development growing pains associated with this (and you have to think very carefully about your keys and data structure) but it's only getting easier with things like secondary indexes and Riak search. If there was a non-expensive way to enumerate all the data in a bucket, I think that'd be the one last item on the checklist before I jumped on it.