I have serious doubts about the safety of flip-face helmets in general.
1. I'm not saying they aren't out there, but i've not seen a single one that passed SNELL ratings.
2. All that flip mechanism takes up space where foam should be to compress in the event of a fall. Last time I checked I don't thing the flip-mechanism compresses, does it?
3. If the latch on the chin bar breaks in a fall, you're now wearing only a 3/4 helmet. The latches I've seen weren't THAT sturdy.
I won't buy a flip up despite the added convinence. The ONLY advantage I can see is catching a sip of something to drink, which you can do in a regular full face with a straw.