Jim, I have not tried these boots, but just wanted to pass on a little related story that may be of interest.
Last autumn I decided to get my wife an early Christmas present in form of a new pair of skates. Some of the best skates made anywhere are from a small company named Graf -- formerly Swiss-owned, now Canadian. Many of the pros use them. Like ski boots, their skates come in different last widths, achilles area profiles, and boot flex stiffness indices. But they take it a step further (pardon the pun) and also build to different instep heights for a really close fit in all dimensions. This is something that ski boot makers really should pick up on and start incorporating in their designs -- check out their site, and walk through the skate selection process, and you'll see what I mean:
http://www.grafcanada.com/hockey/hockey_en.php.
In the shop here (a small, family-run hockey specialty shop....the best kind of place) my wife tried on a few pairs and settled on the model and size that fit best. Next step: heat molding the skates. The young tech put the skates in an oven for about 15 minutes; gently laced them back on her feet, and then wheeled over what looked like a small version of a sauna chamber. "Put your feet in there" he instructed; upon which he flipped on a timer to start the machine humming, popped a video into the little TV in front of the chamber, and said "Relax and enjoy the show. I'll be back in 20 minutes".
The chamber turned out to be an air bladder device that firmly pressed the softened skate boots around the feet to give a custom fit. The kicker is that this machine looked to be at least 20 to 30 years old. Dented, scuffed, noisy....definitely not new technology at work here. I was gob-smacked, having just read all the fall ski magazine gear issues in which everyone was banging on about what a revolutionary concept the Fisher Vacuum Boot was. And here I was standing in front of exactly the same thing, only for hockey skates, and that had obviously been in use for many years.
My point is, that Fisher seems to be doing nothing novel or original here, but has simply adapted a method that has been used by skate makers for quite some time (judging by the vintage appearance of the air bladder machine, it's been decades). Fisher calls it the vacuum boot, but it's really the same idea -- soften the boots, insert wearer's feet, press upon them with air bladders, and Voila! A perfect fit. One significant difference, and which relates to High Angles comment, is that skates do not have removable liners, but ones that are integrated into the construction of the boot. The heat molding forms both the boot and the liner at once.