104mm last: Comfort is key for skiers matching up to this last width. It is roomy and comfortable, making it the preferred choice for recreational skiers that demand comfort above all else. This is the boot type that most recreational skiers prefer.
80 Flex Rating (roughly): Salomon hasn't indicated the true flex rating of these boots. So we've done some scientific tests, and decided this boot is about 80 flex. Its pretty stiff for how light it is, which is pretty sweet.
PU Shell: Poly Urethane shell (plastic) that resists stretching and is durable for long life.
30mm Power Strap: A velcro strap, 30mm in height, acts as an extra buckle to keep the top of the boot together. The 30mm straps are good for recreational skiers or junior racers.
Micro-adjustable aluminum Racing Department buckles: These aluminum buckles can be moved to adjust for size, so if the default position of the buckle and the teeth is too wide or too narrow, you can move it until it fits. And they sport the red and white racing buckles just like the Head World Cup team.
Macro adjust ladder (SuperMacro): The tooth plate opposite the top buckles can be moved in or out for a huge range of adjustment, and to fit narrow to wide lower legs.
Replaceable Toe and Heel Pads: This is a must-have for skiers that don't live in ski in/ski out condos. When your ski tech tells you that you have to buy new boots because the soles are worn down too much, just laugh at him and tell him to order you a new set of sole plates.
Biovent Liner: This liner is highly breathable thanks to multiple layers of foam and wicking materials. Dry feet lead to warm feet, so these liners are warmer than standard liners.
XFIT Fusion Advanced Liner: The XFIT Fusion Advanced liner is still going to be very comfortable, with pretty plush insulation and extremely soft faux fur, but the Advanced version (versus the comfort version) is a bit more rigid of a liner, adding responsiveness to the boot as a whole.
The Big Fella Corollary: We list flex indexes and generally that will be how you determine the level of a ski boot. For ski boots that are very large, you can also take into account the size of the skier using the boots. A 6'5 260lb guy is going to flex his boots more easily than a more averaged sized man, and hence need to ski less aggressively than the flex might indicate. So maybe the boot says it's an upper-intermediate boot, but if he is a Big Fella that is only a lower-intermediate, he still will be able flex the boot comfortably. (The same is true of ladies, but 'Big Bertha' Corollary seemed sort of offensive).