I think you need to do both. When I was learning to play tennis, at the end of the "Introduction to tennis" section told us this. I have used it in as many aspects of my life since as I could.
He told us, "Kids, you have now learned something and accomplished something by finishing this class. To improve, you need to find people better than yourself and play with them. To give back, and to ensure that there will always be a better player willing to play with you, you need BE the better player and help out others who haven't learned as much as you."
So, be both an ambassador by playing with people who are learning the basics, and also a student by playing with people who are better than you. This works best if you only go one or two steps better or worse. I wouldn't expect to be able to sit in and play with Doc Watson, and probably wouldn't learn much from him because he is SO far advanced that I wouldn't have even a chance of figuring out what he's just done. (No comment against Doc Watson, whom I have heard is among the nicest kind of people).
- Zurf