This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
I have some experience in Spring but not in JSF. So I can tell you JSF background is not required to learn Spring.
People in my team prefer using Spring over JSF because I think Spring is more powerful and flexible.
I do not have experience in JSF so other guys would tell you the comparision of the both.