which one do you guys think is better to have by your side in battle ?

I like having a dremora lord (markynaz, the one you summon using the sanguine rose) by my side jus for the pure fact he looks like satans personal bodyguard

Not too fond of the flame atronach cus it reminds me of a transvesti..think its cus of the way it moves lol

but which of them is actually better to have by your side? and why?

dont care about the frost atronach (its too big and it gets stuck in tight spaces) or storm atronach (same reason)

By looks, or abilities?

By abilities, Which of them is the stronger of the 2. Which one is best to take into a battle.

Flame Atronachs are the weakest atronachs you can summon. A dremora would (and frequently does) tear them apart.

The dremora, by several landslides. = D

Unless your opponent is going to be flying around (thinking Dragons) and never on the ground, Dremora Lords are several orders of magnitude better than a Flame Atronach (or any Atronach for that matter).

Its not the actual dremora lord though its the dremora markynaz u get from the sanguine rose and im guessin the markynaz is weaker than the conjuring an actual dremora lord?

as you level up, the dremora that you summon changes and becomes more powerful. E.g, if you are below level 19, you summon Caitiff, between 19 and 27 you summon Kynval, etc. I believe that the system of rank comes from oblivion, like the ranks of daedra in the Oblivion crisis. If you summon markynaz, you would be between lv 36 and 46, The only more powerful dremora is Valkynaz, which is summoned above level 46. See the ES wiki page http://elderscrolls.wikia.com/wiki/Sanguine_Rose_(Skyrim)

Ahhh i never knew this ! ive been using the sanguine rose from lvl 20 and im now lvl 44 and ive never noticed the dremoras name change before.. cheers bro!