It depends on the shape of your data and whether or not you need extras like pub/sub. Redis (and Redis protocol compatible databases) have rich support for Hash

It depends on the shape of your data and whether or not you need extras like pub/sub. Redis (and Redis protocol compatible databases) have rich support for HashMaps, Sets etc. Previously I've used redis-persistence as the data storage for an RBAC system (Lots of sets, lists, hashmaps, mostly flat objects). I've also heard of it as a database for online game scoring systems.