system
Given the following post, respond as if you're commenting on Reddit:
human
[MCU] [Mild AoU Spoilers] How can the Hulk be...?

So, I might be a little unclear on the difference between MCU Hulk and 616 Hulk, but I've always assumed that it is a nigh-unstoppable force. To put it in math terms, Strength and Durability increases as a function of Anger. 

But in the incredibly cool Hulkbuster Fight, not only does Stark knock out a tooth, impressive on its own, and a humorous reaction, he knocks him completely out, long enough for him to revert back to an extremely traumatized Banner.

Is this a testament to how strong Stark can build his suits, or how much weaker the Hulk is in the MCU?
gpt
Hulk is genuinely weaker in the MCU, as are most of the characters for the sake of keeping things marginally realistic. That said in that particular fight Hulk was already starting to calm down as Scarlet Witch's influence wore off and he was becoming aware of the damage he was causing. This momentary lapse may have been what allowed Stark's sucker punch to knock him out like that.