I have the Vans Aura Dual Boa's and I haven't had a single issue with them. I find them to be absolutely comfortable. I never have to readjust the tightness once I get them locked in.
The reason I like the single boas is when I get on the lift, sometimes I tap the front and release some pressure, then spin the wheel a couple of times at the top and my feet get a nice "airing out" feeling for a bit.
(1st post, hello!
My Vans Encore single Boas did break after 50 or so days of riding, but other than that, I like them.
I got my wife a pair of Vans Mantra single Boas, but she took out the liner and cut it with a knife before I knew what she had done, so I just used a Boa off her boot and she got some mens Burton Ozones which are SO much lighter than the Vans.