WF barbarian armor

[Erethrin]

is taking adamatium body removing any ability ? like a heavy armor for other race ?

should i just use composite armor instead (while having low dex) cause barbarian ac wont be high enough anyway ?

[Arianrhod]

WF barbarians don't lose anything by taking adamantine body - except a feat

Since most barbarians use either HP or DR (or both) as their "AC" at higher levels, many don't bother with a body feat. Of those that do, many will swap it out by 10th level or so, going for a more damage-related feat instead. That's one nice thing about saving the free feat swap you get for doing the Dragonmark quest - you can start with admantine body (which can definitely make the early levels less painful), then swap it out for free once AC becomes less useful to you.