I used 9588.com to book domestic flights in China (Shanghai - Beijing - Xi'an - Chonqing - Yiching - Shanghai) with no problems at all. All were ticketless, and worked smoothly. I probably missed some last-minute deals, but having everything in place in advance saved a lot of anxiety.

MU coach was fine; as everyone else has pointed out it is as good as if not better than US coach. But don't arrive at the gate at the last minute. One flight we took was wheels-up 18 minutes before the scheduled departure.