Finished Hunter's Run two days ago... I want to avoid spoilers in my remarks.
It's different. It seems like any other sci-fi thriller, but after about three quarters of the way through I realized it's more like To Kill A Mockingbird, Les Miserables, or Atlas Shrugged. Now I'm not saying Hunter's Run is the same class as those books, but HR delves into the age old question "What does it mean to be human?" I think most sci-fi that deals with the nature of humanity (it's morals and motivations) either comes at the issue from man v. robot or man v. alien. HR comes at the topic from much more in the vein of literary history.
The protagonist, Ramon Espejo, wonders what it means to be human. He wonders who he will be in the future. He wonders about his life's jouney. Who is he? Who has he been? Who will he become? And how much control does he have over any of it?
Of course this leads the reader to ask, "Who am I? Who will I be? This is not my house. This is not my beautiful wife. My God, what have I done?"
Yes, the story has three authors... but it never struck me as disjointed. In fact, it was seemless in my opinion... but I'm not the sharpest tool in the shed.
HR did not grip me like Fevre Dream. The setting was strong and well done, but did not quite amaze me like FD. Although, the world of HR was well thought out and well realized.
I can say that Martin put in his bit to the story right after he wrote FD and in both FD and HR you get a strong sense of Mark Twain's influence on Martin's characters and themes.
I apologize if my remarks were a bit ambiguous, but I was trying not to give anything away because in spite of the deep themes of the story, it's told as a thriller... i.e. the plot has some twists and turns.