I do not have first hand experience with the vsx-72, but I have the model it replaces, the vsx-54. I absolutely love this thing. I compared it against the Denon avr-3805 and the Yamaha rx-v2500, and chose the Pioneer.
If I were upgrading, I would seriously look at the 72/74 (I want firewire/ilink!). There are several changes from the 5x to the 7x, the most significant being a switch from mosfet amplification to more traditional pushpull. As a result the 72 weighs less than the 54. Generally this would indicate a smaller amp section, though in this case it could represent a more efficient/ less heat producing amp which would require smaller heat sinks. haven't seen a real review of either to find out how large the supply is.
The MCACC is excellent. I love the ease. in the past, reviews have indicated that Pioneers version of auto-eq is one of the most accurate around, perhaps because they were one of the first to offer this feature. I believe they have upgraded this even more on the 72/74. The video switching will definitely be a big convenience feature. If the 72/74 are true upgrades/improvements over the 54/56, then without hesitation I would recommend them!
The best thing to do is to listen to receiver with speakers as close to or preferrably identical to the ones you will be using at home. You can decide if you like the sound, as well as get a feel for the user interface and remote. Be sure to listen in the "direct mode," which defeats tone controls and MCACC, when making your decision. The reason for this is to get the true sound of the receiver. You can adjust the sound of the receiver however you choose with the eq features, you want to make sure that you like the basic sound of the receiver.
Hope this helps!
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