I can tell you first hand that there is a waiting list for people to get in to see Mumia. A ladyfriend was fortunate enough to spend time with him and upon meeting her, he encouraged her to learn about the prisoners at SCI Greene and to make sure she came back to visit them.
I have never been to see Mumia myself, but all reports are that he is a generous man who cares about his "colleagues" and is in the struggle with goals larger than simply saving his own life.
This was in another post, but it is applicable here...
"If we get this guy, we can get anyone."---a guard at SCI Greene responding to a question about how important Mumia's case is to the death penalty in the United States
You can question the motives of some of the people who have latched onto his movement, but I don't believe you can question Mumia.
A good point was raised in this post about other political prisoners and I wondered if folks think the same argument can be applied to Leonard Peltier. He is not nearly the icon that Mumia is, but I think his case draws similar interest from folks who follow humanitarian trends.
---I'm here---
"Ten out of ten heroin addicts started out on milk."---from Arliss