
Looks and feels nice (until it crashes). I monitor four different accounts. Which means with Mailspring logging into every one of them when starting the app.. Every. Single. Time. Garbage app.
I really wanted to love Mailspring, and it almost became my daily email platform. Unfortunately there are some issues at least for me, and I understand this is a subjective review that may not apply to all. That is what I love about reviews though you get to learn about specific use cases. The big design issue is the lack of disabling threaded conversations. It's non-existant, and it's a major backward step to omit this. Lots of people asking for it for years but no movement on design policy. Secondly, the flatpak is a little glitchy and has issues integrating with your browser when needed, or password apps, etc. There are some really low level design aesthetics I also scratch my head about, but look its a beautiful looking design overall. I just can't bring myself to use it as my daily driver's main email client. Back to Thunderbird.
Mailspring is beautiful, modern, smooth e-mail client. Works very well for me. But it still doesn't support POP, which made me use it for just a few weeks.