I've really enjoyed owning the 436 amps. They are relaxing, yet detailed, have great grip and control of your speakers, the imaging and soundstage are first rate, and the tone nuetral to a little on the warm side. To no surprise they do run hot, and the fan/chimney system does a good job. If you can swing it provide a dedicated line to each amp in a poor man's balanced configuration. Also I've had great success with Synergistic power cords/interconnects, and speaker wire. As for the Thetas, I've not heard their amps but assume like other Theta products I've heard sound very good. I'd be glad to speak with you offline also.
Steve
Steve