- Depends how sophisticated the 'digest' needs to be, but inbox groups messages very well, can be trained/configured, and easy to review a set of similar emails (like mailing list or forum updates) and swipe done or for later. First time I've managed to get to and stay at inbox zero for work and personal accounts.
I was one of the first users of inbox and use it every single day. It helps organize my mail in such a way that improves my productivity. The ability to add reminders is a real plus.
It took me just 4 days to get used to it coming from traditional gmail desktop tool.
But once I could manage the initial learn curve, it really improved my productivity specially with reminders, smart suggested answers and how it groups different kinds of emails automatically.