I'm considering switching from Gmail for similar reasons - multi-second delays when switching to a label are kinda unacceptable. But this is 2014, and if I'm g

I'm considering switching from Gmail for similar reasons - multi-second delays when switching to a label are kinda unacceptable. But this is 2014, and if I'm going to switch, it needs to be to a desktop application so that I can have some vague semblance of security - at least supporting PGP mail and accepting messages which happen to be delivered securely with STARTTLS without the possibility of eavesdropping on my end, even if most of my mail is never going to use PGP. Plus, my laptop almost certainly has more CPU to spare than some random cloud server, so in theory searching should be faster, even if the rest of the UI can be equally snappy in a webapp as in a desktop app. Unfortunately, after trying several candidates, I have yet to find an app whose UI I actually like, so I'm still using Gmail. I think I will try Mailpile once it's ready.