This is most powerful apocalypse, without his horsemen.
@Dextersinister: Yes! That is a part of it. Iron Man would be screwed. Now Ultron is almost a stalemate. Very powerful. Ultron is practically indestructable. Apoc maybe able to survive even as small molecule, but Ultron can just strike powerfull blasts that would destroy every molecule of his body. Ultron would probably win if not stalemate Apoc.
Does anybody have any of apocalypse feats? I am not extremely familiar with the character.
1. Apocalypse was capable of withstanding a fully-powered telekinetic blast from Stryfe at the end Messiah War. It did not affect him at all. If Wolverine were in Apocalypse's place, then he probably would have been disintegrated or violently thrown against the wall. Also, Bishop and Stryfe were not able to even kill a weakened Apocalypse.
2. In X-Cutioner's Song, a weakened Apocalypse was able to defeat a team of X-Men in a minute, if I recall correctly.
3. He managed to engage Jean Grey on the astral plane for a particular period of time.
4. In The Twelve, he also managed to easily absorb Cyclops' energy blast, and Cyclops was enraged at the time.
I hope that helps. :)