Ok, I can weigh on this after several sessions on the 12m Razor and a couple of higher wind days (18 - 22 knots) on the 8m Razor. The Razor definitely boosts quicker and with as much if not more height than the Rise. The float is definitely less, but since the Razor is a bit quicker through the wind window and likes to set lower in the wind window, when you go to send the kite it generates a quicker, stronger pull.
Coming down has some float, just not as much as the Rise. Definitely have to work the kite.
All in all after 3 sessions on the 12m Razor, very happy with it. Haven’t gotten out on a light day with the surfboard yet.