I'm playing a character who uses heavy armor, and even of the helmets I've found, these outclass everything. Good base armor stats (23) and awesome bonuses? And you don't even need smithing skill or a high level to get them, they're just loot on bosses.

I think the only ones that can be better are forged/enchanted items you make yourself.

You're still better off delving into enchanting and smithing. With smithing you can also improve the dragon priests armor and with enchanting you can make armor that's best tailored to your style of play.

Once you start levelling Smithing, even shitty vendor-trash armor has the potential to be badass.

Aren't there bonuses you can get for having a full set of the same type of armor? So while the base stats on paper wouldn't be as good, there'd be a bonus. But I'm basing this off the assumption that there aren't other armor pieces that are in the same "set" as the masks. And that this bonus exists for heavy armor, I know it does for light armor.

Full set of Deadric+double enchantments on each item=unstoppable force of nature. I'm pretty sure I've got 160% added two-handed sword damage, regen stamina at an 80% bonus rate, and only take 30% physical and magic damage at this point. Oh, and I can breath underwater forever. Among all the other bonuses I have from playing the game. I can swim through lava and not die for a while.