It remains to be seen which one will have an upper hand. ISIS definitely has battlefield experience. It's pretty much confirmed that their commanders are ex-Baathists from Saddam's army. When it comes to mounting an assault, taking over a city or fighting an army on a battlefield, ISIS has the upper hand. ISIS also has more recruits. AQ is more adept in suicide bombing, planting IEDs, attacking police headquarters and making quick escapes. Meaning, they're better at insurgency.