Best boot ever for response, but...
I actually own last years model (2012), but almost nothing has changed. Best boot I've ever owned (other boots are Ride Insano 2013 and Burton SL9), but there is definitely room for improvement. Here are the issues with this boot:
1. It's not warm, I always have to take a break after a couple hours on any day below 20F to warm my toes up.
2. The drawstring cords for the shell break easily, but I also like my boots very tight. (broke both of them, but should be easily replaceable)
3. Not a fan of the clips that hold the cord tight, they hold the cord if you pull them at precisely the right angle, but it's not as easy as it should be.
4. It might be that the cord came loose on a really choppy day at Copper Mountain or that the heel hold design on this boot pushes to hard into my Achilles tendon, but I believe that this boot has caused my front foot to have an inflamed Achilles tendon and since switching to my Ride Insano's the inflammation has reduced and I can take more runs before my ankle starts to hurt.
But then again like I said the F4.0 is the best handling of any boot and it definitely improve my skills as a rider (especially in the trees, I was able to go full speed and still be confident that boot would respond quickly). FYI my binding are the super stiff 2013 Salomon Caliber and I've used this combo on all my boards from flexy to stiff to powder.