mutt is more powerful than Pine, vastly more so for those of use who learn to configure it. It's my primary mailer, Thunderbird my sencondary. But,
Pine is user friendly. It's doesn't have a GUI, but still has a menu system that makes it almost as user friendly as a GUI mailer. To many people I know, it is invaluable. It's what works without learning a bunch of keystrokes, whether you need to log in from a foreign remote Windows machine (no X, don't want to set up IMAP) to read mail, or if you just want a lightweight mailer.
I'll be looking for a replacement, possibly Alpine, as suggested in this thread, when it goes beta, whereas I'll reserve the mutt recommendation to power-users.