ncache

I am trying to move my app to out-of-proc session state and can't find which session object is failing to serialize - the YSOD stack trace is unrevealing. Is it possible to view the objects, or at least the types of objects, currently stored in session state of a running application? Short of attaching a debugger to a running app, and having its source code available, I don't know if this is possible. I'm using Alachisoft NCache, so here's their stack trace, though it's not helpful: System.Web.HttpException (0x80004005): Unable to serialize the session state. In 'StateServer' and 'SQLServer'

Has anyone done a thorough comparison of AppFabric and NCache or AppFabric and ScaleOut? We are currently looking to implement either AppFabric, NCache or ScaleOut for distributed caching in geographically distant locations and I would like to know anyone's thoughts who has compared them side by side. I appreciate that many people use one or the other and tell me why their chosen solution is great but I am really looking for a comparison of the two products. Such things as what does AppFabric not do or not do well (if anything), partially from a features point of view but also from developer's