I personally believe that I would rather know who I get to work on stuff I'm paying them for. That's just my opinion, however. I believe that the more I am acquainted with someone, the more likely they are to know what I want and how I want it done. If you are naturally talented and receiving a lot of request, I recommend the first. You get the job done, and you make a profit. You may not get friends out of the experience, but if you are really interested in said person, you will talk to them anyway.