Another one to consider is www.9588.com. I've booked with all three (elong, ctrip and 9588) at different times, and haven't had any probs yet.

Elong was a bit of a pain - yep, they made my fax in a copy of the cc, and it was a paper ticket, so I had to meet someone at Shanghai airport to collect the ticket. But they got the ticket to us ok, so all was good in the end. (that was in November 06, don't know if it's still the case).

I've booked a private taxi through ctrip, and was happy with the driver and the price.

Have fun