Both of the McCormack Amps are of excellent quality. You won't be unhappy with either of them. As the birdman stated the DNA-2 is rated at 300 W into 8 ohms and the DNA-1 is rated at 185 W into 8 ohms. A more significant difference is that the DNA-2 is a ballanced amplifier design while the DNA-1 and 0.5 are not. If you don't have an extreemly demanding set of speekers to drive you can't beat the deals on the used DNA-1s. Get the Deluxe versions as they have better input and output connectors as well as some other upgrades. There was a DNA-1 Rev A for just under $1700 if I didn't already have a DNA-2 myself I would have bought it.
John
John