I have had it on a duergar. I like Dwarf and Duergar because the spiked armor stuff had decent ac on it, and I could build a real nice suit that activated it.
Its been years, but I beleive there is an echo when its at a level high enough,

I remember seeing a svirfneblin rager with it, he had stone skin, resistence, and the ac bonus and took very minimal damage, he was very mean.

Figure out the best race to build a high ac set that is effective..... If Jinroh used it, his logs would be a good tip