I'm not familiar with that one. There are an abundance of to-do apps; everything from simple lists to shared project management level behemoths.
These days I use the native Reminders app. My needs are light.
I used to use Toodledo, a cross platform app and web based to do list (when I had an Android phone in the Mix).
Before that I used Things, an iOS and Mac OS X app with lots of features. I liked it a lot, and would nave gone back to it, except I retired and no longer need the extra features.
Things is heavily influenced by the GTD (Getting Things Done) method created by David Allen. If you are familiar with that workflow, you'll find all the usual tools.
And while it's not exactly a to-do list, Evernote has the ability to turn notes into tasks, and make check lists. It's a kind of in-betweent thing that can be handy for organizing projects. I don't use it for day to day tasks, but I like to use it when planning home projects, like when I built my stairs. It lets me not only track the tasks, but document the plans, purchases, and take notes while shopping for supplies.
