In Luca Bolognese's PDC presentation on ObjectSpaces, he stated in a diagram that you should use ADO.NET's objects DataSets/DataReaders if "You require maximum control/performance/functionality" That seems to indicate that we should not use ObjectSpaces if performance, funcationality and control are a requirement. If this is the case, it would seem that using ObjectSpaces in WinFS is very contrary. WinFS has to be quick...not just fast...lightning fast. We are talking about impatient users.
I think it is important that we get Mike Deem to respond to this in his Blog. I am going to forward this to him and post it up on the newsgroups, but maybe I am missing something.