Do the thread makers here intend this to be the "dc vs marvel uberweapons" thread that they almost always turn out to be? Since I'm pretty sure someone will bring up Batman can find a way to get the anti-life equation or steal myx's powers or something like that.
I always assume prep would be whatever tech the character can build on their own. Maybe allowing alien tech if they understand how it works completely and can reverse engineer it I guess.
So using my rules (which may end up just being used by me) I say Batman. Seen more impressive tech by him when he needed it even if he doesn't use it as much as ironman. And he's a better strategist in general. He won't just build 1 thing that will beat stark, he'll build 10 to beat him in 10 different ways, just in case stark goes in a slightly different direction in his prep than batman predicts.
just my opinion anyway