Genos, definitely. IRon Man is still a regular human under the suit, Genos is an incorporated android/cyborg. He can take more damage than Iron Man, and his power outputs that we've seen have dwarfed the power Stark has shown
@AshChrimson Yeah I mentioned that... After doing some more research I found this... http://static.comicvine.com/uploads/ignore_jpg_scale_super/11111/111118857/3118025-comic+scan+74.jpg. Sure this is his Extremis armor... not his Mark 6... but if we're going with that one I have no choice but to give it to Tony... so I guess it just depends on which suit we use... but if Tony calls this one it's over... I see I severely underestimated Tony's newer armors. I apologize. But one final statement... a misconception I wish to rectify... beating Hulk isn't that impressive as he starts out weaker than the Thing, but has an exponential and unlimited growth, making him dangerous. Sure taking down a infuriated Hulk (as Tony did in World War Hulk, though Hulk and his army did kinda tear the world apart) is impressive, especially since this Hulk beat Black Bolt... but regardless I concede defeat. Thank you for showing me how wrong I was. I'll do more research and see which versions of the armor Genos could take and where the cut off-line is. Thanks.
@AshChrimson The fastest speed the Mark 6 (which is his standard armor) can go, allows him to keep up with Spiderman. While that's impressive, Spidey's real strength isn't moving distance, but reflexes, and with web swinging he (going off of Spiderman 2, since finding exact speed in comics is hard) can keep up with a NYC train, so that put him around 150. According to a speed calc by segamarvel, Spidey can go 144... so I'll stick with my earlier 150 estimate. Genos is fighting an opponent that can move at beyond supersonic speed, making him at least 768 mph. Way faster. Also, while Tony can use his sensors on tech, there's no reason to assume that the tech Genos has exists in the Marvel Universe. In the Iron Man Armored Adventures, he is incapable of processing Doom's technology, confusing it for magic (which he wasn't using at the time... though I know he can). Sure he might be able to, it's purely speculation on both sides since we don't know what Genos is made of, but there are a lot of insane things in the OPM universe. Tony's strongest attack, the Omnibeam, could probably hurt him... since it did turn an enraged Hulk back to Banner (though he had to absorb most of Earth's energy to do so)... but not beat him, because A, to get that much energy (the whole earth thing) would take a lot of time, B, it would totally drain him and Genos could kill him, since he can literally fight with one leg left, and C. Genos has stalled those far beyond mountain busters. His own lasers can easily cut through mountains. Scan here; http://static.comicvine.com/uploads/original/14/148711/3946297-3194335089-onepu.jpg And as for Hulkbuster, as stated by Tony, it can lift 175 tons... the Mark 6 can do 100... it's not that much of a boost, considering the huge amount of speed it sacrifices... sure it has a lot more firepower... but none of that will hit Genos. If they're bloodlusted, or if Genos is just serious, he could incinerate Tony before he gets a chance to summon the Hulkbuster, since he did do that to a mountain. While the Endo-Sym armor might have a chance, it's big thing is energy absorption... which won't do him much good against Genos, and doesn't really have any feats beyond that. But that's my two cents. Feel free to point out anything I missed or got wrong.