[Update] Ken Case comments below, addressing some of the concerns listed here. It looks like a future version of OmniFocus on the Mac will be able to directly update the OmniFocus reminders on the server, removing at least one of my complaints.
Ken Case from The Omni Group has been twittering for awhile about the impending inclusion of alarm reminders for OmniFocus. The task management app's iPhone users have been pestering The Omni Group to implement reminders as push notifications, but OmniFocus refuses to do so. They say that reminders that rely on connectivity are not good enough, and they have instead chosen to implement reminders by exporting due dates and times into iCal. Once the time comes for a reminder, it pops up like a normal iCal appointment reminder.
Well, OmniFocus 1.5.2 for iPhone was released, and now we get to see how this alternative reminder system works. If I had to choose a word to describe this implementation, that word would be "awful." Here's why:
The Omni Group has taken great pains to point out that you do not need to be using the desktop version of OmniFocus to get use out of the iPhone version. But for users that only have the iPhone version and are not synchronizing it to either MobileMe (which has a yearly fee) or a WebDAV server (complicated for non-techies), they can't use this implementation of reminders. That's right; the way it works is that OmniFocus on the iPhone exports your reminders to your synchronization server, then points iCal on the iPhone to the server to import your reminders. That means that if you enter new due dates in OmniFocus for iPhone but don't happen to have connectivity, you won't get reminders. Wait, I thought it was implemented this way in the first place to guard against a lack of connectivity?
Your OmniFocus reminders unnecessarily pollute your iPhone calendar with reminders. This is a visual problem when you need to glance at your calendars and see what actual appointments are coming up. On the iPhone you can either look at one specific calendar, or all calendars, so if like me you need to regularly stay on top of more than one calendar, you're forced to look at your OmniFocus reminders as well.
Oh, and even when you complete them in OmniFocus and resync, they don't go away in your calendar.[Update] Stephen points out in the comments that this works as expected, and upon further testing I have to agree. Maybe I was being a bit too impatient.
Since your OmniFocus reminders are actually just fake appointments, there is no way to audibly differentiate them from appointment reminders. They sound and look exactly the same. Remember the Milk, for example, uses push notifications on its iPhone app, and you can set the notification sound to a number of different options. That way you know that you're being reminded of a task rather than an appointment.
Reminders are set based on Due time, rather than Available time, and in terms of flexibility you can set the reminder to be 5 to 60 minutes before the task is due. By the time a task is actually due, isn't it too late to be reminded about it?
Finally, if you're a user of OmniFocus for the Mac, your reminders are not created on your iPhone until you think to launch OmniFocus on the iPhone and synchronize it. That means that if you work all day in OmniFocus on your Mac (like I do), then drive home and start doing other stuff and don't happen to open OmniFocus on your iPhone, you won't receive any reminders for tasks that you might have set for that night, or until you actually open and sync OmniFocus on your iPhone.
So, what would I rather see? Push notifications, like the many other OmniFocus for iPhone users out there that have been providing their feedback to The Omni Group.
As mentioned, Remember the Milk has implemented push notifications, and the ability to change the notification sound isn't the only trick it has up its sleeve. The Remember the Milk icon on my iPhone's screen shows how many due tasks I have that day, and the number changes almost instantly when I make changes on the web version. To see how many currently available and due tasks I have in OmniFocus, I again have to launch the app and wait for it to synchronize.
While I love OmniFocus and I think The Omni Group does amazing work, this implementation of reminders for the iPhone version of OmniFocus is just full of an amazing amount of fail. It's a hacky workaround that still doesn't ensure that a lack of connectivity won't adversely affect the user's ability to receive reminder notifications. Omni folks, this is just meant to be tough love -- I wouldn't be saying all of this if I didn't truly care about OmniFocus.