As you can imagine, MX vs. ATV Reflex involves zipping around dirty places in a variety of scruffy vehicles with honking great wheels. Interestingly, the aforementioned beefy tyres carve up the track as you race, changing how it plays.
The PC edition will include what THQ calls the "huge added bonus" of the "substantial amount of dynamic downloadable content" developed for the console editions. As far we can tell, this amounts to two track packs with extra vehicle skins and clothing.
While there'll be a retail release of MX vs. ATV Reflex in Europe and Australia, in North America you'll apparently only be able to buy it through Steam.