I have heard a lot of good about JSF but as far as I know people also had lots of serious complains with this technology in the past, not aware of how much the situation has improved. We are considering JSF as a probable technology for a social network project. But we are not aware of the performance scores of JSF neither we could really come across any existing high performance website that had been using JSF. People complain that it is too slow & about its scalability issues.
We are still not very sure if we are doing the right thing by choosing jsf & thus would like to hear from you all about this & take your inputs into consideration. As for the backend we are going with a NoSQL database.