Personally I believe that the Dragoon (non advanced) is best, as it has some great hit and run tactics (pounce onto a human, rip his head off, then pounce away, repeat untill all humans are dead, sing robot song
"the humans are dead
the humans are dead
we used poisonous gasses to poison their asses
and now all the humans are dead!")
(actually this would be better with an advanced basilisk...)
The advanced dragoon is not worth the extra evo, as it has a really difficult ranged weapon and eats humans just as fast. my second favorite is the advanced maurauder, as it has an awesome fear inspiring ability, and is nigh on impossible to hit in some maps. just try and win whilst I wall jump around you (the pillar room in arachnid 2 comes to mind) and fry you and your mates till I have three flash-fried humans. Then I start the teabagging...
Tyrants, the only thing they can do better than any other class is make the less experienced players wet themselves. oh, and they are great for ghosting because of the way their 'claw-arm-tentacle-teeth-thing' hangs out in front of them just above a human's head height. But other than that they are really useless. They deal masses of damage, but are always first to get shot at, Have a speedy runaway mechanism, but can't jump any higher than your kneecap. I have a feeling they are probably very succeptable to GTFTS (Go The Fuck To Sleep, a nickname for any highly potent sleep spell from a role playing game like CoC, D&D or similar, slightly boring games(I just do CoC)) I think that the mass of health has no effect when as soon as you walk through the door, everyone stops shooting the adv mauraurder directly in fron of them and shoots you, way to waste five evos. The final problem is that whenever you die, the guy who got the last hit just has to teabag you, except he has to jump to get above your massive corpse. just wait till it sinks into the ground, but if you kill a tyrant with a lucifer cannon you just got the least effective gun ever to do what it was supposed to do!