Checkmark builds on location-based reminders. What's nice is that you can create buttons for oft-visited locations (and choose a custom icon) for super-fast reminder creation. I've got my kids' schools, the post office, grocery store and less concrete spots like the bus stop and what I call "my neighborhood." Events can be triggered when I arrive, depart or, get this, within a certain time after arrival or departure. For example, "Remind me [X] fifteen minutes after I arrive at the library."
Once things are set up, a reminder can be created with three taps. That beats Reminders and is a heck of a lot faster than Siri's hit-or-miss dictation translation.
Snowman has teased the app today, and we assume it will launch before too long. When it does, we'll post a full review. It's a sweet little app.