From my experience Lotus Notes is only marginally better than cc:Mail. While Notes has many more features and may be less buggy, it is very counterintuitive with ambiguous settings and options menus, and replication features that most users would never be able to figure out without proper documentation and training. The nonstandard interface made it especially difficult for our employees to migrate from Outlook. Unfortunately it's our only option for business email. Of course Notes also offers the calendar, to do list, and address books, but so do most other email programs in a much less confusing manner.
For personal correspondence I'll stick with telnet and Pine.