Atma's is already an efficient item for those that can use all of its stats.

2400g cost.

+45 armor (worth 15x45 = 675g)
+18 crit (worth 50x18 = 900g)
+40 AD (assuming 2k health... worth 1600g)
----------------------
3175 total value for 2400g cost. This is pretty decent.

BUT if you can squeeze out another 28 AD out of it, that bumps the stats gained by another 40x28 = 1120g, or you are getting 4295g worth of goodies for 2400g. VERY good!

Considering Tanky-DPS Atmogs is part of the new metagame and it yeilds 0 MR from the two tems, would it not be a simple counter to simply grab yourself a Madreds and rip them?

thoughts?

Force of Nature scales well with Atmogs, because of the %max HP regen. Not only are you taking reduced magic damage, but weak dots like Toxic shot you can actually shrug off and ignore.

One game I was in, I'd excaped a teamfight after soaking enough damage to leave me at a thin sliver of my HP- and teemo comes from the side and gets off a single AA/blind/AA combo on me, as I just keep running.

Besides, even against Atmogs, Madrids are fairly underpowered, except on a few champs.

Chain helps counter ranged AD carry.

Sh!tloads of HP counters burst.

You have some added dps and you are hard to kill. Its useful

been owning with nasus, i get mercury treads > trin force > warmogs > atmas and if the game is still going force of nature...and if its STILL going...guardian angel.

i like atmog builds so much :3 very fun and good.

i want udyr next...

this is a good guide for all the great atmog champs http://www.mobafire.com/league-of-legends/build/the-way-of-the-trinity-force-atmogs-114755

There's a major point no one else has touched on that allowed Atma's and Warmog's to become so prevalent. That thing is farming. The current meta-game is so focused on pure farming and late-game viability that it was natural to gravitate towards an item path that emphasizes this ideal. Both items are expensive and don't really pay off until you purchase both, and to do that fast enough to impact the game you've gotta farm.

Item synergy aside, I think this is the main reason. Especially when you consider that not too terribly long ago, Warmog's was considered one of the worst items to buy (in spite of the math proving otherwise; I'm merely pointing out public opinion and how it shifts according to what the "pro" players decide to do).