I have an admission to make: I haven't played the original Risk board game. For hardcore fans of the game, that fact alone may discredit my opinion. However, after playing the upcoming XBLA adaptation, I wish I had discovered the board game sooner.
Risk Factions looks and feels like a Penny Arcade game: the art style is similar, and the writing is just as irreverent. As evidenced by the shorts released by EA so far, the world of Factions is animated (in more ways than one). The Colonel, who's fully aware that he's in a game, is one of the funniest characters I've seen in recent memory. Knowing his audience well, he promised that if I kept playing, I'd see tons of nudity in the game. (An EA representative hurriedly reminded me that it was just a joke, though.)
While Factions will allow players to play classic style Risk, newcomers will undoubtedly want to play through the main campaign first. The campaign does a good job of easing players into the basic rules of the game, and offers shorter, focused, objective-based challenges to conquer. The level I played didn't take place all over the globe: instead, it was a rather small map comprised of about a dozen tiles. One tile offered occupation of a missile silo, allowing you to launch a devastating area-wide attack against enemies.