I hope I'm not violating any rules by posting a link to arfcom, but here's a thread discussing SCAR vs. XCR. If the link doesn't work, the thread is called "Initial Impression of The SCAR; Not Impressed" and is in the FN Herstal section under their "Armory" section.
http://www.ar15.com/forums/topic.html?b=6&f=24&t=295328
http://www.ar15.com/forums/topic.html?b=6&f=24&t=295328