I would say his Thorbuster suit was probably the most durable mainly because it was brushing off hits from a Skyfather (King Thor). His second most durable would probably be his Iron Destroyer armor from Fear Itself. The material in it was magically enchanted Uru metal (same stuff Mjolnir is made out of). Third would probably be Bleeding-Edge because it took hits from Thor and an amped Grey Gargoyle (amped by the Serpent and he was amped to Thor levels of strength, power, durability, etc.) and Ulik (amped by the High Evolutionary). Hulk-buster (from World War Hulk) was probably the fourth since it tanked plenty of hits from an enraged Hulk. Then I'd say Extremis is next since it tanked two really hard hits from Odin Force Thor, Sentry, and Hulk. He also tanked a nuclear explosion in this suit.

I would say his Thorbuster suit was probably the most durable mainly because it was brushing off hits from a Skyfather (King Thor). His second most durable would probably be his Iron Destroyer armor from Fear Itself. The material in it was magically enchanted Uru metal (same stuff Mjolnir is made out of). Third would probably be Bleeding-Edge because it took hits from Thor and an amped Grey Gargoyle (amped by the Serpent and he was amped to Thor levels of strength, power, durability, etc.) and Ulik (amped by the High Evolutionary). Hulk-buster (from World War Hulk) was probably the fourth since it tanked plenty of hits from an enraged Hulk. Then I'd say Extremis is next since it tanked two really hard hits from Odin Force Thor, Sentry, and Hulk. He also tanked a nuclear explosion in this suit.