Got to say, I've been getting more and more fond of the creaky little Scorpion lately(creaky in that a strong gust of wind would make it explode :P). It's amazing for taking out other land-based vehicles, particularly the Manta... those plasma ribbons are absolutely lethal. Vs foot troops though, I'd go for a Hellbender, Manta or Goliath, in that order (but they're all great). My particular favourite tactic is to take a Hellbender (even if nobody else hops in-- actually that's preferable) then camp near the end of the central gorge, so you can alternate between defending the central node with the side-turret and taking potshots at people leaving the base (if they're losing, natch) with the rear turret. That rear turret is absolute ultramegadeath vs pretty much every vehicle other than the Manta, and stationary snipers too.
The problem with the Hellbender is that it is so freakin big, just like the goliath, driving round in one is just like sticking a huge neon sign on your back saying "im over here, please shoot me" although if two other people are manning the guns you can cause some damage...mwaha :D
Well, you have to be pretty sneaky in the way you use it. It's amazing for camping, nobody can get close cos of the side turrets and you can't be out-sniped cos of the rear turret.
i like the scorpian and the goliath
Have to say the Scorpion hands down. The Manta's too hard to control, the Raptor's too vulnerable, the Hellbender is okay once it's properly manned and the Goliath is cool but really needs backup. Can't wait to see the Leviathan and space craft and the hidden vehicle (see my thread) :)