I've got one and it's good. The open/close mechanism from full face to open face was a bit stiff when I first got it and the instructions were poo, which led to me scratching the lid before I'd even worn it on the road by trying too hard with the flip mechanism, causing a 2mm (ish) scratch at the rear on one side, which is annoying but doesn't affect it. I should touch it up but never get round to it. Once I got the knack of opening it, it's easy peasy.
It is heavy but you don't feel it in use (a bit like a GS
) either closed or open. Very comfy. Visor only steamed once as I recall and that was in monsoon conditions (had to stop riding it was so heavy - couldn't see
). Internal visor is grand. I use it much more often open face than I ever thought I would. Nicely balanced.
I strangely find it quieter than my Shoei Raid II, although flips are traditionally considered more noisy
You could flip from open to closed while on the move but I wouldn't recommend it - the chin bar flips up past your line of vision before resting behind the main part of the lid. I don't think you could do the opposite - in my experience you must use 2 hands to free the mechanism from open face back to full face. Just stop for 5 seconds.
Turbulence wise, I haven't noticed much when riding open faced, but can't say I've ridden that way at constant speeds of (say) 90 mph+ when it may get a bit more turbulent.