I used 9588.com to buy tickets for domestic travel in China during June and July. No problems at all. I was concerned that I would arrive at an airport only to find that the airline wasn't set up for electronic tickets, but that worry proved baseless. Also, every day that I was scheduled to fly, I received an SMS message with confirmation of departure times and weather in my destination city (in Chinese). I assume that was from 9588.com, but I could be wrong.