This BTL bridging feature sounds like marketing hype to me. I had an Arcam avr300 once which had a similar feature which didn't so much.
This BTL--Bridged Transless--design supposedly eliminates a capacitor in each amplifier circuit which may be a reason for the mediocre increase in power. I doubt one would detect much difference in performance and there is some argument it may add to distortion. Also eliminating capacitors has to impact damping factor and the ability of the amp to respond to quick demands for voltage. I don't see much benefit and actually see potential problems.
