The vantage is an awesome helmet. I used to use a Smith variant brim and switched when the more low-profile Vantage came out. This helmet will keep you warm on the cold days and protect your dome when you smash it on the ground. Pair it with some Smith I/O's for a perfect google/helmet combo. I think Smith helmets fit a little big, so I typically order a M instead of a L.
I have had three variant brim helmets, and all have worked great. The helmet will keep your head safe & warm, even on the coldest of days. The vents work well, but will sometimes stick if snow or ice gets in the holes. You can also remove the liner if you want to wash it after a sweaty adventure. However, if you want a more low-profile look, go with the Smith Vantage.
I've been using the Smith I/O's ever since they came out and i've been thrilled with their performance. The google gives you a great field of view and includes with two lenses that are easy to swap out. The I/O's are compatible with almost any helment and I like the Smith styling on the strap. Definitely worth the $$.
I originally bought trekkers because I wanted to use an alpine binding when skiing BC. Don't do that. Trekkers are horrible and the touring experience is guaranteed to put a black memory in the best of days. I was pysched to sell them on Craigslist.
Compare the GP chesty (2:20) and head angles while skiing.
The Chesty is nice at it is out of the way and doesn't have the "gaper"look of the GoPro on the top of the helmet. The angle is great for biking as it gives a good perspective of the arms, handlebars, and trail. Unfortunately, isn't ideal for skiing as the lower chest angle doesn't show the terrain as well. Go with the head mount for skiing and take the GP off in the lift line ;)
Mounting a ski forward isn't only for skiing switch, but it will allow you to get more of an even swing weight with your ski. This is really nice if you ski trees as you will be able to maneuver and throw your skies sideways easier. If you're 5'9 and skinny, the 179 will be the better length, unless you are a true slayer :)
I ride the 179's mounted with Dukes mounted at +4. These skis are sick for both resort and BC days. The Dukes have always kept me in my skis and released when I needed them to. I think that you will like the fatter and higher tip on the Obsetheds over the low profile tip of the JJ's. PS - never use trekkers, they are horrible.