I am with Parc now with Capitol. I was luckily steered towards them by a bunch of expat pilots. They are not as experienced in China as a couple of other agencies, but they are probably the best overall agency out there. Rishworth at the moment is behaving themselves in China. Their local rep is good and his english is excellent. Unfortunately it is still Rishworth. Eventually the scum down in Auckland won't be able to help themselves and will revert to their old ways, which eventually means your paycheck comes up short.
Parc is not perfect, but some lifetime contract pilots told me that long term, they have always been the best. A couple have said they won't work a contract unless Parc is their rep.
My experience with them has been good so far.