I used Air Asia for the first time and this will be my last.
I wanted to drop my bag at Kona Kitabalu airport and saw long lines of people at self-check-in counters. There were only a few machines fully functional (some were only for printing boarding passes) so I lined up for one line and realized that I couldn't print a bag tag and moved to another line - like three times. There was no staff assisting people so many people were confused with this and how to use the machines. It was a mess.
Then I noticed there was a separate check-in counter for Int'l flight. Since my final destination was Tokyo, I lined up at this counter and waited for some time.
A female staff at the counter was just so cold and unhelpful. She told me I couldn't check in at the counter because I had separate booking numbers for two flights (this was caused by some issues during booking). She told me to go back to self-check in kiosk, print out a bag tag, line up for a bag drop line. I can't believe she couldn't really help me. There was nobody waiting behind me (so it was not like she was too busy with other pax to assist me).
Also I didn't find Air Asia that cheap. You can only have 7 kg of carry-on luggage for free of charge. I had to pay the fixed price for 20 kg checked luggage just because my luggage was 1 kg plus (8kg).
I would avoid this airline in the future if I have to go through so much hassle to fly somewhere.