All really cool boards. I ride an amf split and wouldn't wanna ride anything else. I also rock a solid amf for sled shuttles. My wife rocks the NS split and it helped to progress her riding leaps and bounds. One of my best buds rides the helix and loves it. All three are actually pretty different with the variations in camber. Definitely try them or a similar camber if you can. NS exels when going really fast but wollows when you slow down at all. The amf is not as playful as the helix or NS but the little bit of camber with rocker tip and tail gives me the stability at speed and for larger airs that I was looking for.... U really can't go wrong but they are all pretty different.
I can't comment on the boards but I will say that I feel that a set of spark blaze binders will be more playful than a karakoram set up. The split 30s felt like they were sitting on a solid block of aluminum under foot. My boards definitely had a different flex with the two. The karakorams seem to sit higher off of the board as well. Both are great but have a different feel.