I’ve heard several “rumblings” from Microsoft as well as other “Archiving Solution” vendors regarding their take on Exchange 2010’s built-in archiving features.
I thought Martin over at Archiving101.com has posted a great write-up about this topic. If you are considering on waiting for Exchange 2010’s archiving capability to do your corporate archiving and E-Discovery, I’d recommend you take a look at his post.
http://www.archiving101.com/?p=178
Take care!