i have delta mvmnt dfc's and love them, definitely very responsive and sturdy yet flexible. I would recommend them to anyone who rides about 30% all mountain 70% park. As for the 390's some of my friends who spend almost all of their time in the park love them. I hear they are more flexiable then the deltas and have some cool features to them such as the straps have like a spring action to them so you can step cleanly into the binding without having to hold them out of the way. Either way i dont think you can go wrong, two great companies and two great sets of bindings.