Berserkers are equally capable of being good or evil.
If they're good, then out of battle, most will brood about whatever it is that causes their berserk fits, or show remorse about losing control of themselves. Most end up one of two ways: being taught by their teammates to control themselves after a particularly close call, or dying in a dramatic fashion while lamenting that they died without completing their mission.
Good Berserkers are also very prone to Heroic Sacrifices, for very obvious reasons. When this is not played for drama, the Berserker may have a Boisterous Bruiser attitude when not in his battle rage.
Evil Berserkers, on the other hand, is generally just unrepentantly Ax-Crazy and very often Chaotic Evil.