Actually Martok, there is only one folly that tops his. And that is, "Never start a land war in Asia."
Sorry, I couldn't resist...
Anyhoo, back on topic.
Both designs have their merits. I do like both designs and would gladly take either one, if given the chance.
This is strictly my honest opinion, of course.
On Range: The X-Wing I will admit has the longer range and the FTL Drive gives is a distinct advantage.
On Firepower: I would give a slight edge to the X-Wing (4 Laser Cannon and 2 Proton Torpedo tubes to the 2 Turbolasers on a Viper). The Laser Cannons and Turbolasers seem to be equally destructive. It's the Proton Torpedoes the give it a plus.
On Manueverability and Speed: I would have to give the edge to the Viper in these catagories. I think a Viper would even give a TIE Fighter a run for it's money (may even a bit better).
On Versatility: I would have to give the Viper the edge. It can be used for Recon, Long Range Patrol, Strike missions against Capital Ships and Planetary Bases and defend against enemy fighters (even at 2-to-1 odds and a bit higher) and it still comes out victorious.
On Targeting and Scanners: Would have to give this one to the Viper. The Colonies do seem more advanced in this catagory.
On Shields: The x-Wing does have better shielding and seems to be able to take a bit more punishment than the Viper. The R2 unit helps that equation out.
On Dasher, On Dancer, On Prancer and Vixen...
OK, I'm getting punchy here. I gotta go now.
Peace out.