The Shark Spartan Carbon is THE best lid I've ever owned. I've had Arai, Shoei, AGV, Caberg and OGK lids over the years but I'd rate this one above them all. That obviously is a personal opinion. The Spartan is quieter than my previous AGV. It fits spot on, initially it seemed a little tight but it eased up as the miles went on. I tried a mates identical lid on first and would always recommend trying first rather than buy blindly over the Internet.
The Spartan has outstanding peripheral vision compared to some lids I've had. It came with a black and clear visor, both with pin locks. The venting system works really well and the drop down internal visor is a bonus. The visors are ridiculously easy to swap over too, a very clever mechanism has been thought out on that.
One thing I've really been impressed with is the lack of buffeting in the wind at speed compared to some lids. So those 'spoiler wings' on the back really do work.
Finally, build quality is sublime, easily equal to a lid costing twice as much.
I'd buy another. I'm definitely a Shark convert now.