Mcintosh mx120 vs 121


What does the mx-121 have that the 120 does not. I found the mx-120 for less then 800 at a local store and trying to figure out if its worth it or save for the 121??
lkruer
The 121 pass thru 3D on the video side, The 121 is offered as a lesser priced MX151 where as the the 120 really was closer to the MX136. So I think over all the 121 would be a better performer on surround calibration.