The AKs are sick, so much float, though they like to turn a lot. They are a bit softer than the JPs. JPs love going fast and straight, although they aren't as stable as ANTs at speed. Seth's I haven't skied, but my brother has them and loves them. He skied the AKs and ANTs (but not JPs) They are more stable than the AKs at speed, and a more versitile all around ski. Compared to the JPs, I don't know, personal preference. The Seths are stiffer and like to turn a little more, the JPs softer and ski straighter.
If you have another pair of skis for park/all mountain, buy the AK's, if not, the Seths are some of the best all around skis, but I prefer the JPs. I just love going really fast and straight, and like a bit of a softer ski. I recommend demoing them though, because everyone is different. Also, don't forget to try Gotamas.