What was so bad about the non-Windows interface other than it wasn't Windows? I didn't have problems with using Notes email or developing apps for Notes. It had incredible workflow and database replication features. Blew anything Microsoft had at the time out of the water. When I was forced to start using Outlook, didn't care for it. Still don't think it's all that great. I guess Sharepoint is decent enough now.

Sure I guess if all you cared about as an end-user was email and Windows-like UI, then I guess I understand. But you were missing a ton of other things.