You'll get some differences of opinion about whether stack height helps or is useless, largely depends on how much and how hard you carve. I happen to like the biomechanical advantage it gives for most skis, not just 68 mm carvers. But I have funky knees that need all the help they can get; YMMV.
IMO, the various Tyrolia/Head combos offer slightly different strengths, as DD's link shows. You need to do a cost-benefit of adjustability vs non (cheaper), and of elevated vs non (cheaper), and of binding movement in both directions (RF, cheaper) vs fixed toe, movement of heel (FF), and oh yeah, if you travel at mach speeds, whether you want the damping from the springs in the FF.
But keep in mind that the cost differences in $ are fairly small over the lifetime of the binding. Your call should be more about the differences in convenience, feel and handling. IMO the RF is a major convenience, but only if you like to play around with boot location for different terrain. If you do, get it, period. OTOH, the performance differences from a plate, or from and flex pattern, will be subtle, maybe you'll notice, maybe you won't.