Been using the Mozilla suite for email since the late 1990's and migrated to Thunderbird some time in 2003-2004 if I recall. I've never really bothered with spe

Been using the Mozilla suite for email since the late 1990's and migrated to Thunderbird some time in 2003-2004 if I recall. I've never really bothered with speed or understood why it was a concern with a POP/IMAP email client, and that's never been a reason for me to use it. Migration of my mails from Mozilla to thunderbird was trivial since they used the same mbox format. I've moved my thunderbird profile after that from Linux to Windows to Mac, across nearly 20 years, with no problems. I will continue to use Thunderbird for the simple reason that it just works on all the common OS'es and it's easy to move your profile across them.