[jkbyc]

A comprehensive list of them is at http://nosql-database.org/ a comparison matrix of Mongo, Couch, Dynamo, HBase, Cassandra, Accumulo, Redis, Riak, Neo4j: http://www.infoivy.com/2013/07/nosql-database-comparison-cha...

There is so many of them that I doubt there is a good resource comparing them. I think it's best to start comparing the various models (document store vs column store vs key-value store vs graph db vs rdbms, ...) and then look for detailed comparisons of the implementations of the model.

There is a lot of hype around many of them, but a lot has already been debunked too, esp. here.

For example I personally would have picked PostgreSQL rather than Mongo in some cases in past when Mongo was pushed on me by people who's understanding didn't go beyond the hype.

Maybe describe your problem in more detail here and perhaps you'll get useful feedback? Maybe Ask HN? Feel free to drop me a line.