Style-over-Substance if done properly is an amazing thing and Refn's Drive is a great example of this. The opening chase/hide'n'seek scene is flawlessly executed and sets the tone to the rest of the movie, aswell as introducing us to the nameless protagonist in an interesting and effective fashion. The rest of the movie plays very much like the opening scene as far as style is concerned and it works extremely well. The picture looks fantastic as you'd expect from the director of the visually astounding Valhalla Rising.
The story is incredibly simple, the way it is told however is highly complex. The Driver's personality remains a mystery from beginning to end but develops a relationship with a woman called Irene (Great performance by Carey Mulligan, sweetening the otherwise rough and explicit escapade of violence and revenge. Refn has a way of portraying violence in a stylish manner without taking away from the shock factor. It's a very mature piece and definitely not something I'd recommend to kids. A lot of people criticize Drive for the excess of violence but I personally think it is necessary to tell the story and for the characterization of the driver.
All in all, I'd highly recommend Drive as it is one of the best films of 2011.