Replying to Shift or CAST Binding Systems?

Hey all, I'm currently looking for a setup that'll be used next season.

I'm mainly a resort skier but I'm looking to get into the backcountry. I love the freeride aspect of skiing... jumps, drops, spins, pillows, and steep lines. Considering that I'll be skiing the resort a lot, which is typically blown out, and doing an occasional park lap, (I have park skis but just in case I want to do one through the day) The CAST looks like a sturdy setup that I'd trust but I've heard lots of great things about the Shift. The Shift is cheaper overall but I want to know which will be a better choice. As a side note, I'm not sure of what skis I would mount them to yet and It would be a 70/30 equation. (70% resort / 30% backcountry)