i've heard the ra972; haven't heard the 985bx, but i did own the rb980 and rc980 separates, which i believe are the same series. in general i don't think the rotel will be a quantuum leap over your nad; i think you'll find the nad more "alive and dynamic" (as you state), esp. in the lower end. (btw, i like that "warm and mushy and chocolatey"). if you're looking to change, i'd listen to rega or my fave, arcam.