I keep two email applications - Evolution and Thunderbird. I use GNOME
so Evolution comes as default email application. I want to use it but in
practice this software is just too slow and simply freezes / crashes
when Internet connection is off even temporarily. When it does freeze
it's not easy to close or shut down. There's just so many user issues
with it. So I install Thunderbird. It comes with all the features that
equal Evolution and it's fast. Fast enough. Plus it integrates
encryption and signing with gpg.