On my trip to Bali I had the opportunity to fly both airlines as I had to make a quick trip back to Perth the first weekend.
Garuda. Had more legroom, was cleaner, searved a nice meal and the option of watching large number of latest moves, tv series etc.we were also allowed up to 30
Kls of luggage. Air Asia however was more cramped ie:less legroom. The Aircraft arrived late and turned around almost straight away, meaning that it was given only a very quick clean. The arm rests have only one button and that controlles the tilt. The meal that I ordered never arrived. I was told that I did not pay for one, yet my bank statement says differently. But looking at what other passengers were served, I didn't miss much. I was also charged for wheelchair assistance which was a first, although I must say the service was good if you ignore the tatty old chair in Bali. They say you get what you pay for, but I compared both airlines prices and when you added on the meals, drinks ($8 for a small beer) and baggage to Air Asia prices, there was very little difference. Also with Garuda you do not have to listen to the Captain forever advertising his meals and drinks over the speaker system.