Well, ours is done. We have approximately 100 servers and our last one's to go were Exchange Servers (not my project - Thank you God!). Aside from a great improvement in AD synchronization, I have not seen any difference. However, that difference is significant. A constant pain in the past.
My big complaint with AD / LDAP is in the structure itself. Naming conventions are terrible, structure modification is a fear filled endeavor becuase of the way that it is replicated throughout the server farm, and it does not have any overly friendly user interfaces or nice scripting language (aside from vbscript).
I would love to see the sales presentation that went before MS to sell this as the way to go for the backbone for security architecture storage.
I will be digging into the advantages of native mode as time permits and if I come across anything grand I will be sure to post.
“He is no fool who gives what he cannot keep to gain that which he cannot lose” - Jim Elliot