I’m not sure what qualifies as “real world data” but Giro published estimates when the helmet first came out.

http://aerogeeks.com/...anquish-mips-review/


“Only” 74 seconds slower than a regular Aerohead over a full IM.

If you believe this and the Giro claims the Vanquish is just over a minute slower than an Aerohead over an Ironman. I train in one with the visor, race in hot races and love the helmet. You can't go wrong with one IMO.
http://aerogeeks.com/...anquish-mips-review/

Cycling Weekly did a test with Aerocoach and there was a video. It wasn’t a killer helmet, but it ticks all your other boxes and it doesn’t suck. If you like the visor though, I wouldn’t shy away from a real TT helmet.

Outside of that test we’d done some other work with similar results - in fact I had a road bike TT I was training for and the choice got narrowed down to a Specialized Evade or a Vanquish for me, and I ended up choosing the Vanquish because I wanted the visor. The Evade was marginally faster on me.

If you want a visored helmet then I agree with the above, a full blown TT helmet will be faster and you can always buy a much cheaper helmet for training if you like?

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AeroCoach UK
http://www.aero-coach.co.uk

To me real world data is results that do not originate from the manufacturer.

I've seen the Cycling Weekly test, but I don't think the results are valid for my use-case; they tested road bike, with either hand posistion top of handlebar or straight arms in the drops, and without the visor.
I would be using it on tri bike with visor.

I started looking at full blown TT helmets, but I do not find many with both MIPS and visor. The Smith Podium was my initial candidate, but in the tests, I've seen, it isn't that fast, which made me look at Vanquish.