Close. Good battle. Well, for one thing Asajj Ventress was Jango's replacement, so if originally Dooku chose Jango over Ventress then I'd assume Jango's more powerful, but then again he probably didn't think of finding a rogue Jedi or even know where to find one. Jango beat Obi-Wan and Asajj lost to Padawan Anakin so I'll say Jango could beat her, at least until she got a year of experience and training from Dooku, because a year after AOTC she beats Obi-Wan (In the Cestus Deception) and, seeing how close the battle between Jango and Obi-Wan was in AOTC I'd say by that time Obi could definately defeat Jango.