I've also got the Vex pedals and couldn't be happier. One of the few pedals on the market I've seen that can actually be switched over for a leftie relatively easy, which is only worth mentioning if you are a leftie, lol. I've tried out quite a few pedals and none of them felt as comfortable as these do. A few members of another forum I belong to suggested trying them with the spring removed on the secondary pedal, and I think this does actually make them a bit smoother as well, so may be something to try if you are a new user, or even if you already have the pedal.
As far as the price goes, they can keep it that low because they do their own advertising, distribution, and sales. As someone who has worked in the music distribution field, I can tell you from first-hand experience that in most cases the mark-up on musical gear is at least 50%. It cost me a little over 2 dollars for Zildjian, Pro MArk, and Vic Firth sticks when I was working at that job because we got to buy the gear we bought at the same cost that the stores were charged. The Vex pedal would easily go for at least twice what it goes for now if they ever did start saling in stores. Just stating that because the fact that it only costs $99 is often mentioned along with "you get what you pay for". It has a 30 day money back guarantee, so keep it in new condition in those 30 days and if you don't like it, return it. The only problem that I've had with it was that the set screws that hold the beater to the pedal itself fell out, but if I had checked the tightness I wouldn't have had that happen. Things work loose, and I can't blame that on the pedal, but instead have to shoulder at least part of the blame myself. The set screws only cost me $1.00 for two of them, though, so it was a cheap fix.