I think the Quad Cannon should react faster then it does, most of the time they get smoked by migs unless you have 3 or 4 of them next to eachother (and not exepcionally fast either) formation(ctrl+F) lock or they all get distroyed by a Firestorm attack.
But for the rest they are quite capable of handeling thereselfs. (placing demo traps everywhere and stinger sites for a little defence and stealth detection, They are so cheap! :D !!) expecially if your in a well working team who can hold off the first attack a little (maybe send 1 or 2 tanks) so you can build 4 rocket buggys wich can distroy almost every tank attack with a rocket barrage, GLA micromangement rulez :smokin: if done right :p !