Bought one earlier this year. My first flip front after years of Arai. Here too it replaced a Tour-X3.
Vents: Top vent is
really good. I never noticed any effect with the little Arai ones, on the Neotec you'll know if you have the top vent open. Front ventilation is ok though I'm not wild about it coming from the Tour-X3, I do have issues with this thing fogging up a bit at slow speeds despite the pinlock. The Neotec feels a bit stuffy but the Arai being half an MX helmet was very open in the chin area. Ofcourse the Neotec is even more open if you flip it open, which is great for puttering around on slowish lanes, especially with the sunvisor down.
Fit: Seems slightly rounder than the Arai. The one I tried on in the shop was a bit more loose than the one they ordered for me. Not a problem in day to day life, but I do have some issues on properly long days like going to the National earlier this month. My head was killing me by the time I got there after about 10 hours on the road. Did some slight foam massaging, felt a bit better on the way back to the ferry.
Note: Feels a bit rounder than the Arai, but will probably be narrower compared to Nolan! Given that I've never managed to get a Nolan on my noggin...
The sun visor is nice and easy to operate. Though the Tour-X wing worked better at keeping the sun out of my eyes in situations where the sun is low in the sky, I do miss that... I commute straight into the sun and that's challenging with any helmet:
Other than that, build quality is nice, it feels solid, not rattly or anything, comfy to ride with the thing flipped open (at reasonable speeds). The ratchet closure strap takes a little getting used to after 12 years of DD but that's no biggie. The only downside of the strap I can think of is that there's nothing to lock it to the bike with on the Shoei (other than pulling a chain through the chin bar).
One minor peeve I have with it is that the lining is far too easy to remove. I usually put my gloves in my helmet when off the bike, and in 12 years of Arai that's never been an issue but in 3 months of Shoei ownership I've already had the entire liner hanging off my gloves velcro strap twice and had issues with it being slightly loose more often. Especially the plastic bit with the snaps above your eyes tends to come loose easy and then flaps around in your field of view.
Another thing I still have to look at is the seal on the visor. I've only had one proper bucketing yet with it, but that time I had water running down the inside of the visor. I've been told they can sort that out in the shop but so far I haven't found the time to get them to look at it.