I just left a contract because of Rishworth. I was at Vietnam Airlines. Not a perfect company but I was treated very well there. I was treated like crap by Rishworth. Every single dealing with them was dishonest and deceitful. Avoid them like the plague.
If they told you they are not recruiting Americans in China, well, I am currently in China interviewing for a 320 gig. Rishworth will TELL YOU something like that because the company won't use Rishworth anymore. Instead of telling you the truth, they tell you the company won't hire you because you are from America, Russia, whatever. I have heard this story several times with people trying to get on with Rishworth. They tell you this so you stay with them and apply for a different company. I have heard EXACTLY THIS SAME STORY BEFORE.
Avoid Rishworth at all costs if possible. Parc is great and DPI I think is OK too.