I used this helmet for freeskiing competitions last year. It is really amazing how well Troy Lee Designs has figured out that level of protection with such good balance and lightweight design. For a top of the line downhill MTB-style helmet, this is your only choice. My only complaint was fogging. If you're at a standstill and you're gasping for air cause you just outran your sluff through a chute and off a mandatory air, you might fog up the outside of your goggle lens. But since the fogging is exterior, all you have to do is start moving again and it clears right up.

If Im getting real gnarly I wear this helmet durring winter. wich like cody and drew metioned fogging of goggles is a potental problem because the face shield reflects your breath back to your face. so... with all full face some modifications to you routine are critical... remove he helmet when possible,(hiking or standing around) breathing through your mouth pushing the air down like your blowing bubbles through a straw.. will help the fog issh.

I mostly wear this helmet biking in the summer. it is really light and comfortable fits with all the smith goggles great, and works well with shades too.

Smith said they only made one production run of this for the 2009/2010 season and they won't be making more. The fogging mentioned is an artifact of the protection. Smith has made several openings with screens to minimize the effect.
This helmet looks 10 times better in person than in the picture.
Sizing - My 'noggin measures 58cm. Sizing says I should be in a M/L, but no way. I had to exchange for a XL/XXL, and needed none of the added padding, so the sizing definitely runs small. If you're 57cm or larger I recommend the XL/XXL and use the supplied padding if necessary. You'll be a lot happier.

After skiing some of the runs at Crested Butte, CO I decided that this would be a good idea for the double diamonds and for when the freeskiing competitions start up. Helmet works great, keeps my head warm and I feel bomb proof wearing it. It does fog you goggles a little, but like said in prior review, it goes away as soon as you move. I wear the Smith Phenom which almost fits, but the Smith Prodigy fits much better. Overall great protection and awesome looks!

I wear a Medium in Smith Hustle so i would think that the M/L in the TLD lid would fit, as it did, but just a little snug. I guess with this helmet you want it pretty tight. As Drew mentioned, I found out that fogging was the main dislike of this helmet. Once I got going again, it did start to clear up a little, but since it was pretty cold, the fog froze and I had to deal.

All in all, the lid works great and offers awesome protection. I wore the Oakley Crowbars with this helmet, and it was a great fit. No gaps whatsoever. If I didn't have to wait in tram/lift lines and fog up, this would be my everyday helmet.