... and cleans out the criminals, ousts the corrupt autocracy, efficiently runs services and healthcare, vaccinates your kids... Yeah, it might be good for a while. Not sure.
In the long run, I don't think they're going to be any more effective than what they replaced.
When the body politic (i.e. nearly everyone) supports the rule of law with a transparent governing process (which includes publishing budgets, new laws, etc. and may also include relatively free and fair elections), that will reduce corruption in the long term.
Otherwise, I think it is inevitable that those currently in power will A) try hard to stay in power, and B) use the perks of office to benefit themselves.
Not that I expect many people in ISIS territory to be having these kinds of discussions... they're all concerned about shorter term issues (like not getting killed).