I've ridden the Crowbars in HI Yellow, HI Persimmon and Blue Iridium. All are amazing lenses for their respective conditions.
The HI Yellow's are great for overcast, snowy, foggy, rainy and night conditions. (Basically, the HI Yellow will slay any sort of low-light conditions.) The blue reflective coating makes them look better than a standard yellow lens as well.
The HI Persimmon is a great all-round lens. They're not perfect for bluebird days, but you won't squint too much. They're not perfect for night riding, but you wont' really strain your eyes for terrain clarity. They are, however, perfect for everything in between.
The Blue Iridium are a fantastic bright conditions lens. They are more versatile than Black Iridium or Fire Iridium, which are exceptional for bluebird but more or less one trick ponies for sunny days. The Blue Iridiums are a bit more versatile if the clouds roll in.
Don't get a lens just because it looks cool, and it will pay off for you with perfect clarity.
Oakley's Snow Goggle Light Transmission Ratings (DIFFERENT from what's listed on their website, which pertain only to sunglasses and not their goggles!)
Clear - 83%
HI Yellow - 81%
HI Persimmon - 63%
Persimmon - 62%
Pink Iridium - 57%
VR50 - 50%
G30 - 30%
Blue Iridium - 30%
VR28 - 28%
Gold Iridium - 20%
Black Iridium - 18%
Fire Iridium - 16%