among many other helmets (arai, shoei, kbc, hsc) I owe the scorpion ex-400.
I am sorry to say this, but it is one of the worst helmets i have ever had.
The aerodynamics are terrible, your head will wobble as soon as you hit 70mph (especially with fz6 standard windscreen) It is also one of the loudest helmets out there. The visor does NOT seal and there is NO adjustment to fix this problem.
Now I am sure many Ex-400 owners will chime in and defend the helmet. What I have said above is just my experience and my opinion, nothing against scorpion as a company, I've owned two of them because the sales told me all my problems were related to the helmet size and I ended up buying smaller one, which of course I was not allowed to return once I found out it had exactly the same issues as the "larger one" :/ (you wear it, you owe it)
IF you wont the best bang for the buck in my opinion, go with KBC's VR-1x helmet. I bought one a while back on sale and love it. I find myself constantly going back to this helmet over my 5x as expensive arai or shoei.
KBC has all the features of the scorpion but it will feel ALOT quieter, lighter and comfortable.
The only problem so far, the visor does get foggy if not treated with anti-fog spray.
As soon as it's time to replace the helmet i will not think twice, I will get another one of these.
Here is a nice review, check out comments by users:
KBC VR-1 Motorcycle Helmet - webBikeWorld
KBC Helmets
recision Engineered!