I love a good running 550. You actually have to work to turn, they are a blast. But I too have joined the dark side, I found a huge difference in my abilities between the 550 and SJ. There was stuff on the 550 I had been trying to do all summer but could only get half way (Nosestab), I jumped on a SJ and was ripping it. I was doing full ones, but I was another step closer and felt more a chance to improve.