I want to buy the new Nike Free Run 2, but I'm a bit unsure of sizing. Advice?

Definitely get the 11.5 or even a 12. The shoe should NOT fit snugly or like a street shoe, it should be larger. Think of your toes in your shoe like passengers in a car. Every step is a sudden stop and obviously when your running it is a much more sudden stop then when you are walking. The problem with a snug shoe is that your toe is going to smash into the front of the shoe every time you take a step, that is going to lead to pain, which will change your stride which will cause an injury or to your toe nail falling off.