I used K2's T1 double boas last year, and did not spend one day in comfort. It probably wasn't the boa engineering's fault, but the technology is superfluous.
I have boots that fit now, with traditional lacing, and I often won't even untie on a 30 minute lunch break.
Also just to point out if these break on the hill, it could end your day unless you are carrying a replacement kit. I had a cable break, had a replacement ship out quickly for free, only to find that my whole ratchet system was fouled/jammed and I needed more/bigger parts and a much bigger headache then expected. I imagine most on-hill shops these days can deal with almost any boa situation and get you back riding, but I could be wrong.
Also the ratchet system is subject to wear and tear, and can loosen up.
Lots of people around here love the BOA system, and I'm not a hater, but keep in mind there are a few pitfalls...
I fell for boa's, but seriously...what's wrong with laces?
If the boots fit, the material the laces are made from is irrelevant.
Thanks for the heads up. I'll just take my old boots and keep them in the car as a contingency.
Thanks again for all the replies. It's nice to hear different sides to it other than "I don't like them just because."