Notes is _terrible_ from a UI perspective. The server side (domino) though was light-years ahead of anything in terms of ideas at least. Combining a CA, distributed, document-oriented database(think mongodb, couchdb), LDAP server, web server and mail server that supports IMAP, POP, SMTP as well as the proprietary encrypted notes protocol.
Agreed. I worked in Lotus Domino for a short while, and it was absolutely amazing for Rapid Application Development of anything that required e-mail and storing documents (or kinda "schemaless" data). It was even supported multiple languages (a declarative "Formula" language, a Visual Basic derived "LotusScipt", and Java(!)).
You could write a decent Lotus Domino app that served up web pages, so users wouldn't have to use the awful Lotus Notes client.
Amusingly, in I think Lotus Notes 8, they revitalised the GUI by replacing it with... Eclipse RCP. Hrmm.
