I've found the secret to dealing with Berserkers at low level is to kite them past your assaults with the ability that lets them get a free shot against anything that moves near them. They don't last long in those situations.
In other news, using the Blaster on a heavy with Heat ammo and then launching it at a Sectopod is very satisfying.
Somehow still don't have the "all research" achievement, but I have no idea what I could have missed. Anyone, please spoiler me suggestions of what I might be missing.