I have used Couchbase in the past and we encountered rebalancing problems and host of other issues. Currently I'm using Redis in several production projects. I'm using redislabs.com which is a managed service for Redis that takes care of scaling your Redis clusters. I've published a video on object persistence on my blog at http://thomasjaeger.wordpress.com that shows how to use Redis in a provider model and how to store your C# objects into Redis. Take a look.
