Sorry, but I'd give this fight to Stark hands down.
It's going to boil down to the fact that Bruce rarely uses or builds powered armor while it's Tony's bread and butter. Sure Bats is a better martial artists, but he'll be in a suit that limits his mobility and is no where near as 'comfortable' as his usual combat garb. Even then, Tony's not going to just walk into hand to hand, he tends to fight as a blaster where bruce is going to be at a further disadvantage.
Batman's one saving grace is that he's a better tactician but by donning the armor he's putting himself at a extreme disadvantage. Tony's armor will be more advanced, more streamlined, and more capable if for no other reason he's had the history behind it. He''s not going to be walking out in a suit that's likely never been through a shakedown, he'll be in a proven design that's had its weakness shored up and compensated for.
batman studies his opponent before fighting as just like stark has some pretty sneeky teck, batman could easly hack tonys files and see the blue prints or hack the gov files and seethe war machines prints and know exaclty how it works, and plus tony can only use one suit at a time if hes to far away from the rest of his suits they are useless, plus batman would have known this and adapted his suit to take on those suits just in case.
but knowing that batman can not kill( moral reasions) but tony might if he felt threatened enough (but thats human nature)
but it would be a good fight to see none the less, who knows tony might actualy win with jarvis hacking batmans suit, ya never know
i like it anyway, but i love tony and batman ^.=.^