Iron Man from the Avengers movie, vs. Batman from the New 52.
One month prep, fight takes place in Gotham to help Batman out. Iron Man doesn't know much about Batman's tech since Batman's so incredibly secretive, he only knows what is publically available (even if it's hush-hush business, like his Tumbler was in the first movie). Batman on the other hand knows all about Stark Industries tech since it's a public corporation that Iron Man is publically tied to, and his suit is public information as well as some of it's more well-known capabilities such as lasers and repulsors.
Who takes the gold?