I'm switching away from hey.com at the end of my term. It's not a bad service, but the UI is absolutely inflexible. The absolute worst feature for me is that the sorting of your inbox (I guess I mean "Imbox") is based the time you first accessed the email. There's no straightforward way to sort by the date the email was actually sent. I asked the support group if there was ever going to be an ability to sort by anything other than the quirky default sorting they've chosen but my query received no response.

This is a shame. I was waiting for some reviews of Hey. The idea is great. And its from a company with great experience in UI. It's early days I guess.