Banner and Cho both think the other's gone rogue. Banner thinks it's his responsibility to bring Cho down (in order to save him, NO HULK SMASH!).
Cho realises that he has to go for the kill though, because he knows/fears the kind of damage a really unhinged Hulk/Banner might do... so he's going for the kill but as a "last resort".
fight takes place in an alternate reality where EVERYTHING in the landscape is made from prawns (except for Cho & Banner and their Banner/Cho-augmented-Tech).
Cho and Banner share the same Tech, normally. Cho just augments Banner's stuff to work with his mace. so they have no new tech, just different applications/augmentations of the tech we've seen them use.
I'm going to have to side with Banner. Cho wold probably use Banners method for creating tech and end up with it killswitched by Banner. In order for him to avoid that he would have to create a completely new line of technology and even then Banner as of late has proven that he is an extremely smart individual and is capable of creating not just tech but manipulating individuals as well as predicting their reactions.
__________________ The end always justify's the means by which they were brought to.