The best replacement for mutt is purebred.

The best alternatives to mutt are rated as following:
★★★★★  purebred
★★★★★  pine
★★★  alpine
★★★  fleabag
★★  gnus
★  sup
★  mailx
★  sendmail
★  pedigree
★  pure breed
  claws
  designer dog
  fleabag game
  purebred dog
  slrn

Your alternative for mutt is not listed? Suggest!
Speaking about mutt, one probably shouldn't forget about attachment.

Other search terms related to mutt and their ratings are:
★★★★★ attachment
★★★★ maildir
★★★ gpg
★★ multiple attachments
You have in mind a companion for mutt and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of mutt in all years. Click on graph for more.
mutt
purebred
pine