The two are construction & sizing. (Confession I have ridden in it yet, but I felt you should know the following when considering this purchase.) First, the overall quality of construction is impeccable, the engineering is impressive, & the design is gorgeous. If you haven't looked at their site yet, httpwww.giro.comusenvanquish, you should. Second, even with MIPS this helmet seems sized larger than their charts. My mellon is right at 56cm at it's widest with my tailor's tape. Following Giro's size chart, I ordered a medium (55-59cm) and I've got way too much room. Even with my thickest winter cycling cap, still too much space. As it is, I'm awaiting the exchange process from the great folks at WBW to get a small. I'll amend the review with riding comments as able later.
I ordered this helmet in February after a long debate, and after a few months can say that I love it. I was really on the fence because it looks really weird in the pictures, but in real life it doesn't have funky angles or strange curves it just looks like a nice helmet. I read a few reviews stating that the back of the helmet is the strangest part (visually), but it looks no different than almost any other modern helmet.
The fit is as good and comfortable as I've come to expect from Giro, with easy-to-adjust straps that don't require much thought to figure out.
The visor fits snugly into position with I believe five magnets that are molded into the top edge of the visor, vs. three very visible magnets on the Air Attack (not visible when the helmet is in place). In the upstowed position, I've had zero issues with the visor staying in place, not even an inkling that it was going to come off going over rough spots. To stow the visor, flip it upside-down and it attaches easily using the rear-most magnets.
Cooling this is what I really worried about, since I came from a Synthe (lost that one to a crash), and I live in the south where the heat indices climb over 100 by mid-June. I've had no overheating issues at all, as this helmet has plenty of ventilation, I'm guessing ducted just the right way, to do the job. And yes, I generate heat I ride with the faster groups averaging 25-30 on the flats. Back when it was still cold, I really didn't have any complaints about heat loss, since I wore a cycling cap under the helmet, but the Air Attack is warmer in winter.
Visibility the visor give me a clear, wide view with no distortion. Along the side edges the visor isn't clear, but had a rim for structural stability which I thought would be an issue, but it isn't. There is a small gap between the lower side edges and the helmet body that allows peripheral vision to see what you need to, and looking to the sides (eyes only) still gives a good view without obstruction, so no trouble with that aspect at all. The smoke lens is dark enough in sunlight, and still good in dusk.
My only complaint is that I cannot order a clear lens for the (few) night rides that I do.
Overall, get this helmet it is comfortable, looks high-end without being edgy, MIPS, cooling, and the reliability of the GIRO name.
I debated this purchase for a while, then caught it on sale last month (still on sale now, so jump on this while you can). The fit is comfortable (medium for my 7-38 head and I have plenty of room to loosen and a few turns of the screw to tighten, so I am not struggling with a helmet that barely fits). Typical of Giro's top-end helmets (I've never had an entry-level one of theirs), the adjustments are easy and I'm expecting no slipping of the straps in their adjusters, since that has been my experience so far.
Aero? Seems to be! Since I'm not the owner of a wind tunnel, I'll have to parrot the other reviewers and say that it feels fast.
The visor..... attaches with four small integrated magnets, unlike the three prominent round ones on the Air Attack Shield. The visor goes on easily, securely, and makes a good seal. There are small ventilation holes in the top of the visor, so fogging won', I expect, be an issue (remember sitting still means no air movement, so even ventilated sunglasses can fog when you're stopped). I've seen many reviews that say the visor doesn't feel secure when flipped upside down on the helmet. There is a little truth to this in that the stowed position of the visor is higher than the regular position, so it does not into engage the channels (that exist for aero purposes and as a consequence, to help keep it securely in place), and only has the back two magnets holding it. This causes the visor to have a little travel, as it can swivel up a little, but the truth is that I've not had any trouble on the road with the visor stowed this way. I've been on one rough patch of road that I hate (the group ride took us there), and I was worried that something would give up there, but all was fine. I've not gone off-road nor done any bunny-hopping to test things, but I'm going to trust Giro's QA on this based on my very limited unintentional test.
Two complaints first, there are still no other colors of visor available other than what comes with the helmet, nor are replacements available. Second, and this ties in a bit to the first, is that the visor sits very close to the face and allows no room to wear glasses underneath without the two touching. I understand why, and love the functionality, and no, I don't wear prescription glasses, but those that do will potentially have a problem, depending on the size of their frames. My personal issue is that with the old Air Attack Shield, if my ride was going to last until after dark, I could wear the dark visor and clear glasses underneath, then stow the dark visor as he light faded and already have on glasses without having to worry about scratching them in a pocket (or using pocket space better left to calories on a long ride).
Great helmet. One small complaint. I cant figure out how to properly secure the visor in the stowed position. It feels like it will fall off easily. This is very easy and very secure on the Aerohead.
Visor is very secure in the down position though.