One of the features in Outlook that makes it awesome at basic task management is its ability to easily set a reminder for an email (read or unread) for followup. A followup would be some sort of actionable task, like needing to send a reply, forwarding the email or a reminder to reach back out to a client. For those of us that aren't working with an Active Directory/Exchange environment, we might not be running Outlook for Mac. So what's a productive member of our Internet society to do when we need to set some sort of reminder from an incoming email?
The answer - while a bit obscure - isn't as far off as you might think. The solution lies in using not one but two apps: Apple Mail and Reminders. With some quick drag-and-drop action, you'll easily be able to set a reminder to follow back up with an email and the item will even include a link back to the original email for easy reference.
It's a shame that using the Flag function in Apple Mail doesn't result in this kind of granular task setting like Outlook for Mac gives out of the box. I find it a bit counter-intuitive to be forced to keep two apps open to process email. Since my only machine is a 13-inch MacBook Air, it's rather difficult to justify the use of screen real estate. Not to mention the lack of support on iOS devices; you can pretty much forget about drag-and-drop of email on an iPhone.
This is the feature I'd like to see Apple give the most attention to in it's next major revision of Mail. If Apple wants to keep up with more popular task-oriented email clients like Outlook, Airmail and Unibox, it will need to make some changes to how it allows users to process email both on the Mac and on iOS. Apple has always fragmented their productivity offering (think Mail, iCal and Contacts) and bringing a more cohesive experience their desktop and mobile platforms may keep consumers from running screaming in the direction of third-party apps.