Excellent for bass
Powerful. Does not care of your speaker impedance curve. Dynamic. If there is sudden peak, it stresses this over. Probably you have to pay 10 times more for getting better amplification for your woofer. I have compared this to mediocre 4x more expensive Yamaha, this blows it away with ease.

On higher range, above 1000 Hz not so good any more. Still with power and dynamics but somehow the sound is like it transforms sinus wave to square a little bit. Also, as tested shows some harmonics there. Could be excellent choice for old and lazy paper driver system. Gives you dynamics and sharpness without need for new drivers. In case you have some metallic tweeters then the combinations is not the best.

But still, for the money it is more than five stars. Would buy again.