I prefer driller, but rotate regularly to fill (and promote). I feel like it's the most versatile class in the game.

• Bugs? All 3 weapons do AoE very well and bring extra utility (robots on fire, enemies frozen, bugs slowed, etc.)
• Stuff on the wall? EPC + Thin Containment Field
• Gotta get somewhere? Drills
• Teammates? C4

That said, they're all fun in their own way.

Edited for formatting

Scout. Started the game with a buddy of mine, he picked Engineer as his main, since these two classes seem to synergize pretty good

Engi all the way! Started building up a scout after 300+ hours of nothing but engineer. Scout is fun, I like the mobility. I love having a good driller in my squad, so I think that will be my next class after I level up scout for a while.

Solo I tend to pick scout just for laziness of getting around quickly. Normally only run simple mission types this way.

In group play I mostly do driller. Even if I'm useless the whole mission I can make up for it with B lining to extraction point. Overall I just like the feel of the class and that I am always making an easy to use hole to where we're going and use later. (Don't worry about the one that leads through a ceiling to my and your death. I'm sure it won't be a problem later in the mission.)

That said I do like all the classes and mix in a healthy share of gunner and engi keeping overall ranks semi near each other.

Started with Scout as it had the most appeal initially. Quite challenging to get into the other classes now. Got that need for speed!