At work the need for no-sql mem cache solution appeared. It should be scalable, secure, highly available. For this reason I started looking at Windows Server AppFabric that has caching functionality. At the same time I am going to talk to my college who has experience in Oracle Coherence development. Particularly I am interested in tuning and usage bottleneck aspects.
I found a good overview (from MSFT of cource) of AppFabric. It was made last year at MIX still a good point to start with.