On a recent trip, I took Jetstar to HK, and Tiger for the return journey. I think it really depends on the aircraft they allocated - Tiger was a lot newer and cleaner. Food wise, Jetstar is way better.
Well, I feel that it's only justifiable to take budget if the savings over commercial is more than 100% cheaper, and more importantly, you're flexible with your schedule and flight postpone/delay is not a problem.