I've been using Snailbox for a few months and it has TOTALLY changed my relationship with my inbox for the better.
Don't let the simplicity of this idea fool you, it's really a game changer. If you're someone who is compulsive about checking email and keeping a tidy inbox this is hands down the best way to make your inbox a calm, productive place.
Only thing I really want is a way to add a couple of VIP addresses who I can designate skip the batching filter, but in reality the people who I'd add to that filter also have my phone number and would text or call in a real emergency.
I'd say that this app is like meditation: the more you *think* you don't need it, the more you actually need it.
Snailbox