Just booked a few flights within China and although ctrip clearly offers more flights and more discounts, Expedia seems like it's catching up (somewhat)...

I booked two sets of flights on Expedia instead of ctrip as:
- Pricing was similar but Expedia does not have 3% US credit card surcharge
- On one of the flights, I could select seats (who knows if they'll actually show up!
- Expedia allowed me to put in my frequent flyer info (it'll be interesting to see if it shows up too!)
- Expedia also allowed to book my whole family (spouse and three kids) at one time, ctrip forces two different bookings

In the other trips, Expedia wasn't close in terms of flights offered or the discounts offered...

Just a data point for those searching...