I have flown many LCC carriers in Asia, and find AirAsia to be quite decent. Yes, you pay for everything, but the prices are quite cheap if you book your fare enough in advance. I'd much rather book on carriers that I can get FF miles, but will sacrifice that for low prices.
I booked a ton of tickets for next year, using their current promotion. Many international locales for $20-$30 each way, per ticket.
I know when I've used booking sites like Kayak.com, Expedia.com and others to compare rates, there was nothing in the ballpark for most of them. JetStar is decent CGK-SIN, and the last time I flew, I think they had a small meal or snack. Would cost $4 on AirAsia.
Every time I've looked at Garuda fares internationally, they are many times more expensive than AirAsia. If they were similar, I'd certainly book them. I've only taken them in FC class before, and they were fine, but not on par with most other Asian carriers. This was on BKK-CGK, so perhaps not the best route to compare them on Intl F, though.