Looking for excellent research business partners

While many of our research projects are done through our in-house team, we have always depended on other research firms to offload the in-house group as well as do special projects. We have some firms under contract now but I am always on the lookout for new options. Does anyone have a favorite research firm they use often? Location isn't a concern as long as they have an office and can do contracts/billing in the United States. Our mix is standard online survey stuff, some secondary intelligence gathering but probably most important is the ability to do good qual. All of our work is B2B.
Appreciate any references.