I also had my first sail on a 2013 Ultrasonic having had the 2012 before. Initial sail was in very marginal wind, I also felt the board was slower to plane than the 2012. It felt quite sticky, around the forward footstraps before it would fully release and accelerate.
Once planning the board sailed nose high, with a good trim over the rough sea I sailed in. This I felt was better than the 2012. Gybing was easier.
Need more time to compare, but initial impression is that most aspects improved at the expense of early planning.