My favorite email application, Mailbox, is shutting down in February, so I am scrambling for an alternative. Fortunately, Mailbox’s trailblazing features have been widely adopted by many of its competitors, so there are plenty options. My favorites are Google’s Inbox and Microsoft Outlook. (Yes, Outlook works for iPhone and Gmail users.)

Mailbox pioneered a strategy for tackling email overload that has dramatically increased my productivity: we should get to inbox zero every day, even if it means postponing answering messages until later. Instead of sitting idle in your inbox, a user “swipes” a message out of the inbox and it reappears if it goes unanswered or if there is a better time to compose a thoughtful response.

For instance, I may wait a week for an editor to get back to me on a story pitch before sending him a reminder email. Instead of staring at the message for a week in my inbox, Mailbox pioneered a “swipe left” feature that allowed users to quickly schedule a time for an unanswered message to pop back into the inbox.

The swipe-based user interface became so popular that top tech companies, including Google and Microsoft, overhauled their email apps to incorporate this new design into their own revamped mobile apps, Inbox and Outlook, respectively.

To quantify which app was the quickest at getting me to inbox zero, I created an experiment with 20 mock emails and timed how long it took me to get through them with Dropbox’s Mailbox, Google’s Inbox, and Microsoft’s Outlook. Mailbox was the fastest.

Specifically, Mailbox took 5 minutes and 8 seconds, Google Inbox took 7 minutes and 15 seconds, and Outlook took 9 minutes and 8 seconds.

But now that Dropbox is shutting down Mailbox, it seems like Google’s Inbox will be the fastest email application.

I will still end up with both Outlook and Inbox on my iPhone. Outlook has some nice features, including Dropbox integration (a backup service I use to store and transfer files). Also, it can be frustrating to use Inbox for some emails, such as when I need to switch a recipient to CC. When one email application fails for some simple reason, it’s nice to have a backup.

I will be porting over to Gmail’s Inbox this week. And, if another great technology comes along, I’ll try to keep readers up to date with more stories on the best apps to tackle one of modern life’s most persistent enemies: the inbox monster.