What don't you like about Thunderbird? I was about to recommend it as an email client to a client but hadn't heard any overt criticisms. Is it good at security but bad at UI?
I use Inbox and Gmail for my personal email, so that's what I'm comparing it to.
I'm not a fan of Thunderbird's aesthetics, but obviously that's subjective.
Functionally, a lot of my problems stem from the Enigmail plugin and Thunderbird search. It really wants encrypted mail to stay encrypted and that means search doesn't work. Last time I looked, there was some hacky workaround with configuring a filter to make a copy of incoming mail and decrypt the copy, but I couldn't get it to work reliably.
