I'm a long time skier turned almost snow boarder. The measurements felt accurate and didn't require any special modification or adjustment. They fit under my ski pants but just barely. Granted I didn't have a ton of wiggle room in the waist to begin with, but these took all of it and then some.
Are they worth the price? Hard to say. The cost seems a little steep for what you're getting, but the end results may be justification enough.
Second snow boarding trip and while the first one ended in my inability to use a chair, this thing definitely took the edge off. Look, your falling. There is velocity, and your arse is the recipient of the impending impact. This isn't going to save you, but you won't feel your gums vibrating. Who could ask for more!?! If you're really worried, or expect to take a 10 foot fall straight on the glutes, maybe try the hard tail version. For a newbie snow boarder, this worked out great.