Ok, I have 2 Exchange 2010 severs clustered as a DAG. Explain this to me like I'm a 6 year old: with 2010 clients and outlook anywhere web based clients why would I need a CAS Array? Newer Exchange clients attach to the RPC service and not directly to the CAS. If one CAS goes down they automatically find the next RPC server.. correct? If not why wouldn't the DAG internal IP address assigned to an MX record work?
Also, if you assign a CAS array I've read you don't need NLB...?