Always a tough one, but for Alienation, it really doesn’t matter. There is no best character class, they are all good. Props go out to the developer for balancing the character classes so well. Each class has it’s own pros and cons, so long as you play correctly, all classes will be good.
I have gone into some more detail on each character class in alienation in this guide. Click here for the Alienation character class guide.
If this is your first playthrough, go for the Tank. It is the easiest class to use. I personally found the bio specialist to be the best character though. It was my preference at least. Since the story is short, and there are incentives to play it multiple times. You will end up being able to play as all character types. This will let you experience them all and pick which one you like most.