I've only flown them shorthaul within Asia. What I didnt like.....
The aircraft cabins that remind me of a $2 shop with black and ferrari red interiors plastered with advertising.
The tacky check-in, boarding and inflight experience. Mostly the people working there acting like they had better things to do than their jobs. The fact the check-in desk was held together with sticky tape.
The seat pitch which made me feel cramped even though I had an entire row to myself.
A late night flight where the cabin lights were left on bright the entire time.
It took just 90mins to decide the LCC experience was something I will never try again. I flew a full service airline back the other way and forfeited my return fare and the experience was much, much better.