Purchased lot of time, I use them for 6 years now and no worries
They are on my benefits to push back all circuits. (DX15)
I also tried other amps. They push you need and are adapted to the power of my returns.
For the price I have purchased (1000 euros for 4), I bought your eyes closed.
Major faults: the weight compared to what is happening now and the sound of the ventilation)
Qualities: the sound, reliability.