Both spells are amazing. Dremora is the ultimate badass.
Can I assume that because of the fact that the Atro uses Shock that he is better in situation where there are more than one mob?

What's the differences between the two.

I've been using both, and I've found the Dremora to be superior against all types of enemies. Frost attacks tend to mess up his game, but most thins using Frost at level 30 die in one power attack, or I kill them for him

It only takes one, max two power attacks against most enemies, so large groups aren't such a big problem. With the 100 perk to have TWO summons, they can take down whole armies.

I use Storm Atronach against archers that the Dremora gets lost on the way to, and dragons. Once a dragon is grounded, I switch them.

Does the 100 conjuration perk affect dremora lords, so you can have two? Also what other perks affect dremora lords?

I am 95 ish in conjuration, with no perks, and use dremora lords.

Yes it does.

Thats pretty savage, might have to invest to get that. Anyone know what other perks affect them?

Anyone?