I fell in love with it at first, quit after five months, and then started using it again (with my personal domain) in January of this year when I started a new job and could officially separate my work email (outlook) from my personal email (Hey). It’s not perfect, but I keep enjoying a few features.
The number one best feature is the experience of screening people out, either after they email for the first time, or after they email too much and I don’t want to hear from them anymore.
The second best feature is the ability to a) know when I’m being tracked, and b) still be able to see the email as it was intended.
Other features I like are set aside for flagging newsletters I’d like to read later. Bubble up for reminding me of things on the day I need a reminder. And, at times, the “focus and reply” mode.
There are lots of other features I find neat in concept, but I don’t need or use them in reality.