Grocery iQ has everything expected from an excellent shopping list application.
Create multiple lists so you can dedicate one to your family's groceries and another for the things you plan to serve at your upcoming dinner party. You won't ever have to worry about forgetting anything because the app allows you to sort your list by aisle.
Grocery iQ also has a lot of useful coupons for well known products. It's well organized, so you can quickly find a coupon when you're next at the check out line.
The one major flaw Grocery iQ has on tablets is actually out of its control. The smartphone version of Grocery iQ and other shopping list apps are more convenient on smaller devices.
Now we just need grocery stores to install tablet holders on their carts.