I'm currently posting from a Super 8 in Shanghai, which I booked via Ctrip. I also stayed at a 168 last November using Ctrip.

In both cases, the Ctrip rate was cheaper than the rate afforded to the highest level VIP cards that these chains offer (you need to pay around Y200 for the cards).

On a semi-related note, I booked a plane ticket on Travelzen yesterday because Ctrip's website was being annoying. While they don't tack on a fee for using foreign credit cards, their exchange rate between CNY and HKD was about 3% higher than spot.