Cumulative Flow Diagrams (CFD)

Hello All,
       I'm planning to adopt CFDs in few of my agile projects. I've heard and read a lot about the positives of a CFD. However I'm curious to know about the pitfalls too that any of you have observed while using CFDs. Any specific points to keep in mind while using CFDs? Does anyone have an improved form of representing cumulative flow ( other than the usual area charts) ?

Regards,
Sowmya