Co-host of the TWiT network's This Week in Google podcast and highly regarded Android proponent, Gina Tapani, has ported her Todo.txt Android app to iOS:

I announced the app went on sale yesterday morning on Twitter, Facebook, and Google+, then Lifehacker ran a post on it. It got no other press coverage. I announced the Android app release in exactly the same way on January 24th of last year (minus Google+, which didn't exist then). If my Googling skills serve me right, Lifehacker did not run a post the day the Android app went on sale, though they did the week before when I was beta-testing it. The first day of iOS app sales was solid: just around 365 apps sold, compared to the 215 I sold on the first day of Todo.txt Touch's availability in the Android Market. That means the iOS app sold 40% more units under somewhat similar conditions as the Android app on release day. Her whole post is worth the read as she discusses how the project came together (it's open source) and some of her thoughts on working on an iOS app in comparison to an Android app.