From Supreme Commander Wiki
The Cybran T2 Mobile Missile Launcher, nicknamed the Viper, is a Cybran unit. This is a tactical missile launcher.
The Viper is the most capable MML in Supreme Commander and a vital asset to the Cybran army. The Viper has the highest ROF, effective DPS (the UEF Flapjack has higher DPS but is more prone to overkill), HP, and top speed of all the MMLs. Additionally, because of its high rate of fire, it overcomes one of the MML's common problems: Overkill. Additionally, the missile the Viper fires splits when attacked by TMDs allowing it to hit consistently even when these anti-missile units are present. (Aeon and Loyalist TMDs divert the missile, rather than destroy it, neutralizing the split-missile ability.)