I have been a big fan of Any.DO mobile app on the Android platform but I ended up discarding it and going for Tasks. I even paid for the ad-free version.
Tasks is a no-nonsense to-do app for Android. It features the new user interface that Google introduced with Ice Cream Sandwich.
Best part is that it works on devices running Android 2.2 or better.
The user interface does not get in way of your adding new tasks. It connects with Google Tasks and syncs your items.
It is just perfect. Feels like a totally native app on the Android ICS platform.