I am with moondog on this.

The way I see this - the most difficult part is not about getting the actual visa and/or the residence permit, but to get all necessary permits, authorizations, etc. leading your eligibility for a new visa.

In the Mainland, agents are practically jokes because many of them simply know how to get money without accomplishing anything. And some of the money you pay may not be pocketed by the agents solely, if you know what I mean. You should never try to find one yourself, but instead, ask for a referral. So that even you may end up spending big, still you are still able to get the visa.