I've had a few Air Asia flights cancelled over the years, usually in advance when they discontinue a route.

Short delays are common, 30-60 minutes.

I actually like Malindo more, and haven't encountered any delays over 30 minutes out of KUL.

Malindo also has first class, which can be cheap if you get it on a sale. I think they also give you 20-30kg luggage allowance per person.