xp 550 eps vs 570 eps

Working a deal on these 2 machines. I can get a new 2014 xp550 eps for $6499 out the door or a 2015 570 eps for the same price. Looking for opinions on better deal. I have a 2010 550eps and a 2015 850sp and really like them a lot. Looking to add a 3rd quad to upgrade my son from a Phoenix 200 to a full size. He is 13 and about 125LBS and has ridden since he was about 5.