ive been using mongo and tornado together for a while, and its great. i initially chose mongo over couch because of its fast ad hoc querying. the python client

ive been using mongo and tornado together for a while, and its great. i initially chose mongo over couch because of its fast ad hoc querying. the python client is also well-written and well-documented. one thing, though, to watch out for is that only the "unstable" dev version of mongodb (1.3.x) has read concurrency - before 1.3.x, mongo uses a global read/write lock per operation. general and index-assisted reads are ultra-fast in mongo, but a bigger map/reduce or group call will block other requests until complete, possibly causing traffic to back up. because of that global lock, all writes block, too, but i've never had a problem with that IRL. writes are super-fast. if you want an orm for mongo, check out mongoengine on github: http://github.com/hmarr/mongoengine/tree/master/mongoengine/ http://github.com/hmarr/mongoengine/tree/master/mongoengine/