* It doesn't show full messages on Android Wear devices. You know, Google's own product. Gmail does.
* I can't figure out how to set up a filter in Inbox. The settings page is incomplete. I still have to go back to Gmail to change settings. So I might as well just use Gmail.
* The pins in Inbox don't sync up with the stars in Gmail. Pins, stars, tabs, automatic Gmail categories, automatic Inbox categories, seriously, can we just have one system?
I'm a huge fan of Inbox, but this still gets me all the time. Inbox was pushed as a kind of advanced application to advanced users, yet I have to go back to Gmail for any kind of advanced settings or configuration. That makes absolutely no sense at all.
If it were still in alpha, i.e. "what do you think of this idea", I would understand that some things are missing and gladly provide my feedback about the concept. But once the concept is verified and being pushed as a kind of "ready for consumer use" beta, it really needs to be complete in features before I would make the switch for real life usage. Especially for a mission-critical product coming from a large company with enough developers.