I've been only using desktop mail until Inbox by Gmail came along (and it's most important features where ported to Gmain). For me email has become my main TODO management. So everything goes into email and I heavily rely on Gmail's snooze to schedule stuff. On mobile the Gmail app is great but I haven't found a desktop client that is nothing more than 'Gmail in a standalone browser'. So I'm sticking with just having an extra tab open with Gmail.