I'm currently playing a 9th level Berserker dualled to Thief. He kicks some serious butt. I grand mastered him in longsword before he dualled. The only drawback is that Berserkers can't specialize in missile weapons. If I had to do it again, I'd probably start with a fighter and give him GM in shortbows before dualling. However, with the Berserker, I can go berserk and it makes me immune to almost everything while I'm berserk.
------------------
Now where did I leave that doughnut?!