I have the mrx500 and previously denon avr4802 really like the arc over compared to the other room corrections out there... other room correction seem to focus the sweet-spot in a small seating area with arc the sweet-spot area seems quite big, actually almost the whole room the only downside (in arc gen 1) seems correcting the subs... but the newer gens seems have over come this issue.

(looks like the mrx500 & xpa-5 will be up for sale soon)

7.1.4 * MRX1120 * M100s * 180HP * 4x M3-on walls * 4x M3-IC * dual XV15se * Shakers