As a contractor sysadmin at the time, managing both Exchange and Notes/Domino, I loved Notes for the simplicity of dealing with backups, to tape and over the VPN.

You mark the database as read only, copy the .nsf file over, unmark the database as read only, done. Brightstor had a plugin for Notes that did that automatically and could do incremental backups with ease.

Move to Exchange and it's horrible single file mail storage solution which was inconceivable when hard drives weren't that big. 10,000 users? It's 100MB of mail so it can fit nicely in a single storage volume. Backups? Well, only at night because you have to unmount the file from Exchange, copy it over, and mount it again, which took a good couple of hours.

I miss Notes "simplicity".