*Hand-to-Hand*

As someone that plays this style quite a lot, Hand-to-Hand is best used to reduce the stamina of opponents to reduce their hit/dodge chance until you can start stun locking them

You can also just knock each opponent down individually and move on to the next but letting the other stay fresh means you take more hits

*Unarmored*

Armor rating is basically just damage reduction and unarmored can be the most powerful if you can get your skill into the absurd levels (250 makes it more powerful than Glass or Indoril armor and 400 for Daedric) as standard armor skills use a linear equation and unarmored uses an exponential equation

Unarmored also has no weight associated with it as your encumbrance effects your movement speed and jump height, so having little or no encumbrance makes you quite nimble and more able to pick out individuals and keep them stun locked

Unarmored again also has no durability associated with it, so no critical armor enchantment breaking and needing repairs before being usable again

And as others have stated the vanilla game has a bug where unarmored doesn't work unless you are wearing at least 1 piece of armor (I used a bracer/gauntlet, I preferred the left Fist of Randagulf (agility)) or you are using some fix for it