I've flown Air Asia since they started and had at least 4 return trips with them in the past year. So far, their on-time performance is pretty good because I've had no delays of over an hour (fingers crossed). Most times, my flights leave/arrive 5-15 min ahead of time.

Of course, some flyers may rant about a bad experience with them but who hasn't with any airlines. I've had major delays (over 6 hours) with Emirates but that's because I fly a lot with them before. So, it's depends on statistics ... the more you fly, the more likely you will experience delays. Otherwise, it depends on luck

Happy travels