From what I've seen, the new Spark System is going to be $100-$200 USD less than the Karakorum system. The Riser system on the Spark Magneto looks much more supportive for climbing which I like. The self cleaning and simplicity of it is the big plus for me. Yes the Karakorum system looks way more neato but in use, simple is where it is at.
I will say, both systems have their positives and negatives. I am probably sounding more down on Karakorum than I should be. They do make a nice reliable product over all. If it is what you like, I don't think you'll be disappointed in it.
I'm totally open to both systems. I tended to the Karakorum, mainly 'cause the transition looked easyer (in the shop, with no ice/snow attached to the board). But you're right, in snow the picture could be different. Yes... the simpler, the better.
I was a bit shocked to hear what a complete setup will cost (around 2300$ was the offer for Solution/Karakorum) thus I don't say no to a cheeper binding equally suitable