I agree, and would like to add that the 3312 may provide more real world power than the UPA, based on HTM lab measurements.
"HT Labs Measures
Two channels driven continuously into 8-ohm loads:
0.1% distortion at 122.9 watts
1% distortion at 143.3 watts
Five channels driven continuously into 8-ohm loads:
0.1% distortion at 82.9 watts
1% distortion at 103.0 wattsSeven channels driven continuously into 8-ohm loads:
0.1% distortion at 79.5 watts
1% distortion at 96.8 watts"
"from CD input to speaker output with two channels driving 8-ohm loads, reaches 0.1 percent distortion at 122.9 watts and 1 percent distortion at 143.3 watts. Into 4 ohms, the amplifier reaches 0.1 percent distortion at 202.0 watts and 1 percent distortion at 225.5 watts."
The UPA-500's transformer size is only 350 VA, and specified power consumption is 450W (Maximum). My educated guess is that the Denon has a larger power supply transformer but less storage capacitance. The UPA specifies 5X80 into 8 ohms and 5X140 into 4 ohms. Those are impressive numbers but are most likely short term ratings and not truly continuous. Class AB (or not) amps just can't produce 700W total continuously with a 350VA (less in W) transformer. Not that you need continuous rating, I am just saying if you want more power, go for something bigger than the UPA-500, otherwise the 3312 does seem like a viable alternative.