I may help you out here by mentioning that the Diamond D3 series is the same design as used in the Arc Audio XXK/CXL amplifiers, which is the same as the Zapco Reference series, as well as the Eton amplifiers...
This one is identical to the Arc 4050XXK or the Zapco Reference 360.4...
They all employ an unregulated power supply, so the output is rated at 12v... at 14.4 it is more like 75w per channel and about 225-250x2 @ 4 ohms bridged @ 14.4v...
So, to sum it up, they have awesome SQ, they are reliable and they have good power output... They also have a small footprint...
So, for $130 it is a pretty good deal, as long as the amp isn't beat up...