I had great sucess in permadeath play with my WF Paladin who maxed DR/Admantine. He hit level ten with zero deaths. I've allways wanted to play a Barbarian so I rolled up a pure WF Barb. I put the Mithril Body feat on him. I used a shield most of the time but found my AC wasn't really good enough and the DR from being a barbarian wasn't cutting it. He seemed to allways take a beating in most fights and he died at level four. So I re-rolled him with first level splash Fighter. That gave me access to Admantine body feat, Tower shields and better AC. I can get the "standing DR" (DR/admantine) higher than a straight Barbarian. Seems like all positive so far.
Does the heavy armor hurt any Barbarian skills or abilities at higher levels? I know the armor check penalties for normal skills, but I'm wondering about higher level abilities.