It all depends on your choice of user experience. If you can live with Motoblur, which is unanimously agreed to be the worst android skin available, go with the Atrix, as it's dual-core processor will be future proof. The Evo has a bigger screen (4.3 in) versus the Atrix (4 in) but it's screen resolution is less, making the display less impressive. Overall, I would say the Atrix wins, with a better processor and better screen resolution, and you can ROM over Motoblur if you are in to the hacking stuff.
