I used mutt+offlineimap for a few years, with a corporate account on an MSExchange Server and the two biggest issues I had (which I hope Aerc addresses) were:

I used mutt+offlineimap for a few years, with a corporate account on an MSExchange Server and the two biggest issues I had (which I hope Aerc addresses) were: * no good way to search/auto-complete addresses (I used vdirsyncer which got me the address book locally but there was no easy way to fill-in addresses when typing an email). * no way to accept calendar requests - I would pull them up on my phone to accept or reject. Otherwise, everything worked quite well, but those issues annoying enough that I eventually switched back to a Windows machine with Outlook. The Email+Calendar+Addressbook integration may violate the Linux philosophy of doing one thing well, but for today's typical office workflow it is frustrating not to have a platform with all three integrated.