I have been trying to figure out why I'm hearing so much talk about how awesome armor is. Frankly, the math doesn't add up. A max rank Steel Fiber on a Warframe with a base armor of 150 would give you the largest gain, of an additional 15.9% damage reduction on their health bar.
Effectively, this is the equivalent of multiplying your health by an additional 1.189. So, a Frost or Rhino with a max rank vitality would have 740 health. They already have 60% damage resist, which is the best with out buffs. If you put on the max rank Steel Fiber, you'd have effectively ~880 compared to a unit that has none. Â An addition 140 effective health is not worth 14 points, if you ask me (7 in the polarity slot).
Everyone that is not a Frost or a Rhino averages out to about 40 armor. That's about 29% damage reduction. So... Someone with vitality and 100 base health would have the same 740 Health.
The Frost/Rhino, compared to them, would have an effective 1072, without using Fiber, and 1393 with Fiber in their diet. This is at least an additional 320 virtual health. And wouldn't you know it, that's the same amount of health you'd get from vitality Rank 7, which costs 9 points.
I suppose you could say that it's a diminishing return. But frankly, armor is nothing without a bucket of health to back it up. If I were spending my points, I really might consider ignoring pumping armor for anything else.
PLEASE Correct me if I'm mistaken in how armor works, or if my math is wrong.