I recently bought the V12. In triode mode I cannot imagine a better sounding amp (I do not like the sound in Ultra-Linear). Like all amplifiers, the sound will depend on the speakers. I am currently using the V12 to drive a pair of Martin Logan SL3. Electrostats are very revealing. The V12 takes the harshness out of the sound while still leaving the detail. I have heard many amps, including the ARC 100.2 and Krell FPB, with the Martin Logans. Nothing I have heard compares to the sound of the V12, especially for $4,000.
The 805C should sound better, but at more than twice the cost of the V12 I do not see how anyone can justify the cost for a minor improvement in sound.
I don't suggest comparing solid state amps to tube amps. Assuming your speakers are efficient enough to live with 50 - 100 watts, you must decide whether you like to sound from solid state amps or the sound from tube amps.
If you like the tube sound, I do not think you can go wrong with the V12.
