I like them very much. You will have to change aircraft in BKK which is a good airport. The crew and food are quite pleasant on Thai and the seating configuration is pretty standard. But do a cost comparison on kayak.com because I'd think that most of the long-haul airlines DOH-SYD would be pretty much the same for service but maybe not for price. I would choose the best price, one-stop (or non-stop) airline.