I was at Lotusphere the year Notes 4 was announced and we gave it a standing ovation.
If you'd ever worked with Notes 3 you would know why.
After switching from Mac to Windows 95 in the mid 90s, I always felt like the Notes desktop interface was a bad rip-off of Apple's At Ease interface. [1]
Having said that, I was always a big fan of Notes/Domino even though the UI sucked hard. This is probably because I was a huge fan of Filemaker Pro on the Mac, and Notes, more than anything else (including Access), felt like the closest thing on Windows.
Notes had an app development platform and runtime for forms, workflow and things like that. Adding Eclipse muddled that aspect of the architecture, too.