Gotham City is a place of the 20th century.
Jango Fett is a bounty hunter who hunt and fight in cities far bigger and also more developed than Gotham.
Batman knows the enviroment very well, but Fett's helmet is equipped with sufficient hi-tech tracking systems to let him find Batman, also he doesn't care about damaging the battlefield, he can simply make a building collapsing on Batman using his blasters to damage the structure or do any other tricks like using the grappling hook on him to block him while he's in mid air and so the list is going on.
Jango has flight advantage, Batman must leapn and use his rope to reach him, his long ranged weapons compared to those in the SW Universe are nothing Fett can't handle or manage to stop.
Jango
I would have to side with Jango. Granted, that Jango is in Batman's turf. You also forget Batman's armor is pretty limited compared to the Mandalore armor. Jango has used his armor, and pretty much it was able to withstand Boba Fett's abuse of the armore later on. On another note, Batman may have gone up againse foes that are stronger and equivalent to him. Jango Fett also survived the Sith War, led the Mandalore during a Civil War at a very young age. In addition Batman, has not explosives and cares for Gotham. The Fett's are notorious for disintegrating every bounty that is wanted dead, and even alive. Jango has long range capabilities with his rockets which by the way was not only one fired as seen in Star Wars EPII. Obi Wan did not dodge it if you watch it, Kenobi did get knocked out of the way. Batman has hidden weapons which has been seen. The Fetts still have hidden weapons never even heard of.
Batman's armor is limited. Fett's armor is Mandalorian, an armor that is known to have limited resistance to lightsaber. It is the same make of armor Darth Vader has. As you remember in Star Wars Empire Strikes Back. Luke was unable to cut through Darth Vader's shoulder armor when Luke did strike him before getting his hand cut off. If that armor is that tough, Batman's arsenals will not be able to penetrate through that armor plate of Jango's. Blaster's however fire plasma, and can cut through Batman's armor.