Ravendb (www.ravendb.net) is a solid competitor.

icey · on Nov 6, 2011

"Raven is an Open Source (with a commercial option) document database for the .NET/Windows platform."

I'm not sure it's a competitor at all. RavenDB is a CouchDB clone for .Net that requires a commercial license for proprietary software.

latch · on Nov 6, 2011

Which has a ton of magic baked into the driver making it unlikely you'll get your data back out via anything but .NET.

rkalla · on Nov 6, 2011

Well put.

plasma · on Nov 6, 2011

Why the downvotes? Why would I bother mentioning alternatives next time, sheesh.