Like many people, a lot of my workflow revolves around email. After years of struggling with the very drag-and-drop-heavy interface of Apple Mail, I switched full time to Airmail. This was also around the time that I finally switched away from POP to Gmail; I could have gone web-based, but I wanted a native client. Airmail mirrors a lot of Gmail's power features, like its one-key shortcuts for processing messages. The additonal benefit is that they work throughout Airmail, including with IMAP and even Exchange accounts.
I would say that I run a modified Inbox Zero approach to email, and those shortcuts really make it possible. Airmail even bills itself (on iOS, at least) as a "lightning fast mail client." Just hitting Y, Y, Y to archive messages is speedy. Things to save for later get labeled by pressing L or moved by pressing V. Upon pressing either of those keys, Airmail would display a pop-up menu — yes, an actual menu — with label names. That could be navigated by keystrokes just like any other menu, by typing the first few letters of a label or using the arrow keys.
I keep my labels to a minimum, so filing could be done in a split second with just three keystrokes. For example, I automatically file away common receipts like those from Square, Apple, and my utility companies with mail rules. But receipts from other vendors land in my inbox. No problem: V, R, enter and they're filed away for good. It can be done in a fraction of a second — or at least it could in Airmail 2.
Airmail 3 is now here and while I love many of its improvements, like more intuitive search and expanded sharing integrations, it's disrupting my flow. Fancy swipe gestures and animations have been imported from Airmail for iOS. For some reason those animations play even when using keyboard navigation. A gratuitous orange bar swoops in when I hit V to bring up my list of labels. They're not a menu any more, and you can search by any substring, not just the initial. But that's no consolation when hitting R too quickly after V doesn't select my "receipts" label, but replies to the message.
All in all, this is a minor annoyance, and one I'm growing accustomed to. I'm still sticking with Airmail as my email client of choice on the Mac. If I totaled up all my time since Airmail 3's launch last month, I've probably come out ahead, since its new search syntax (finally!) lets me mix sender, subject, and body terms seamlessly. And even slowed down by a second or two, there's no faster way to get through filing my Exchange email. A month in, I still slip up occasionally, but I'm on my way to developing a new flow.