I looked at the HMK Boa lace boots that seemed to on clearance at the Edmonton sled and decided not to buy them based on the fear of what happens if the lace system breaks.
I have the HMK boa style for 3 years and never broke a cable, they do tend to loosen up in the first half hour but I just give them a quick twist whenever i stop to make sure they are tight! I love my boots as they are nice and light for a big boot!
I wear Northwave snowboard boots with a similar lacing system, put 50-60 days in em last winter. I didn't have any issues with em. They might loosen a bit early in the day, but thats an easy fix, just pull them bitches back up!
The boa system is sweet, until it snaps, or worse, doesn't let your foot out at the end of the day. With these 'speed lace' style systems, if you break a lace, you can tie them back together to get you through a day or two. Yes, they can break, but so will a standard shoe lace...
I have the helium boot and one thing I found at first was they were hard to get tight like a regular lace system however it is mostly because you can not feel them getting tight like a normal boot and just doing them up snug was good enough as they never felt loose or felt like they were not done up. You don't need to hammer on the lace system. Love the boots though, warm and light.