Checkmark is an upcoming reminders app for the iPhone. And it is awesome.

For some folks, Apple’s default apps are not powerful enough or feel absent of features. As such, many 3rd-party devs have made a name and a living for themselves by building “pro” versions of the apps that already ship on the iPhone. A few examples:

• Calendar → Agenda
• Camera → Camera+
• Notes → Simplenote
• Calculator → PCalc
• Mail → Sparrow

And now: Reminders → Checkmark

Apple’s Reminders app is relatively simple. Your to-do items (a.k.a. reminders) can be viewed based on the list they are in or the date they are due. These to-dos can be triggered to go off at a particular time or when leaving or arriving at a particular location. Or they can have no trigger and simply be an item which needs to be done.

For me, the Reminders app on my iPhone has but one interface: Siri. Though my go-to to-do app is OmniFocus there are often times when setting a quick and simple reminder via Siri is easier.1 Especially when those reminders are location based, such as: “Remind me to swing by the post office and buy stamps when I leave here.” Or: “Remind me to take out the trash when I get home.”

There are, however, two quibbles I have with Siri and Reminders:

• Oftentimes I am in a situation where I can’t or don’t want to use Siri. But setting a location-based reminder manually is a surprisingly arduous task. And if it’s for a location other than my current one, then there is much scrolling to find the entry in my contacts list. Not to mention, if the location is not already in my list of contacts then I cannot add a reminder to trigger based on that place.
• Once a reminder for another location is set, Siri often proves to be unreliable at reminding me. For example, in my contacts I have cards for my local Walmart and Lowe’s, but asking Siri to remind me to buy batteries when I get to Walmart does not always work. The next time I go to Walmart it’s hit or miss that the reminder will actually trigger (why this is, I do not know).

Like Reminders+

Checkmark solves the aforementioned Siri and Reminder shortcomings and then some.

In terms of reliability and ease of use, Checkmark beats the built-in Reminders app in several areas (especially if you are manually tapping in a time or location-based reminder — Checkmark is leaps and bounds faster at this). And, as mentioned above, on more than one occasion the built-in Reminders app has failed to trigger a location-based reminder. With Checkmark, not a single one of my reminders have failed to trigger.

Checkmark’s biggest downside is its current inability to work with Siri.2 Of course Siri and the Reminders app have a few downsides of their own. And so I find myself using a combination of both apps.

What I’m using Siri for:

• Quick reminders based on “here”. It’s easiest to let the iPhone set a quick geofence around wherever I am and then remind me of something when I leave that fence (“remind me to swing by the grocery store and pick up a gallon of milk when I leave here”).

• Trivial, time-based reminders (“remind me to check the brisket in 45 minutes”).

What I’m using Checkmark for:

Where Checkmark truly shines is with location-based reminders that trigger on arrival. It’s fast and totally reliable.

This is something that Siri should be able to do, but in practice I’ve found her to be unreliable at reminding me to get AAA batteries next time I’m at Walmart. Which is one reason I’ve found Checkmark to be far superior to the built-in Reminders app for these types of reminders.

When you launch the app there is a “home screen” with icons for each of your saved locations. I have 7 commonly-visited places set up in Checkmark.

Tapping on a pre-saved location takes you to the list of reminders which are set to trigger around that place. From there you can tap to add a reminder. Checkmark gives you options to trigger the reminder or arrival or departure and even to time-delay it.

It takes a whopping three taps (one of which is launching the app) to get to the screen for adding a new location-based reminder. Put simply: Checkmark is fast. I use it for all my location-based reminders. I only wish I could set a repeating location-based reminder (such as one that reminded me every time I went to the bank to log the miles in Trip Cubby).

Also notable is Checkmark’s conservative battery usage. Nearly all location-based apps that I try seem to drain my battery like its their job. But I have no qualms letting Checkmark run in the background.

On top of its reliability and ease of use is a pixel-perfect design. Checkmark is, in this writer’s opinion, of the best kind of apps: thoughtful, useful, and attractive.