A good brain bucket is safety equipment numero uno on any alpine skier's list. The new thing in helmet design is MIPS: Multi-directional Impact Protection System. It basically involves an inner liner and outer shell that can move separately, so that the force of an impact at an angle – which most impacts are – is dissipated somewhat, instead of all going straight to your head.
Sweet Protection is a top tier helmet maker, and they cut no corners with the Trooper MIPS. It's just a tad on the heavy side – 24 ounces – but that's really just about 8oz heavier than the lightest MIPS helmets out there. The simple physics is that a heavier, bulkier helmet is going to offer more protection, all else being equal. Get a stronger neck we say.
The size M/L adjusts from 55-59cm which is pretty much a normal range, and it feels true to size. You always want your helmet as snug as possible without being uncomfortable, and you shouldn't have any problem dialing in the fit on the Trooper, especially since they include some padding inserts for the truly picky. The adjustment system is slightly wonky, but not a big deal since usually you just set it and forget it anyway. The earmuffs are hollowed out in the center, which makes them less warm than a fully padded ear cover but on the plus side you can hear better, and if earbuds are your thing it'll fit better.
The Trooper doesn't feel that heavy or bulky on the head, even after a long day of skiing. It's extremely comfortable, and the venting system is top-notch. The finish is slick, so make sure goggles and headlamps have sticky straps. It comes with a white cover bag. Minor nitpicks don't detract from the facts: the Trooper MIPS is among the best options out there for protecting the most valuable part of your anatomy not directly related to reproduction. And the Trooper is a damn good-looking helmet, so maybe it'll help there too.