Redis in the NoSQL ecosystem – Blog : Siyelo:
All these different options place Redis in the NoSQL ecosystem somewhere between simple caching systems like memcache and feature-heavy document databases like MongoDB and CouchDB. The question is: when do you pick Redis over other NoSQL systems?
[I wouldn’t limit my thinking to the use cases listed here, but th post does give a quick, if limited, overview. It does not mention all the datatypes or the scripting for example, so make sure you explore Redis from the documentation on outward.]