Just installed an ATI 2005. Haven't had much time to do anything other than listen to music. Had the volume cranked to 0.0db and the amps barely got hot... amazing. The amp is driving Aperion Audio speakers. Left and right speakers are Verus Grand Towers, center speaker is Verus Grand, and surrounds are Verus Forte Towers. All speakers pull 4-6 ohms, and like I said, the amp doesn't even break a sweat. Also, remember if you get the AT3000 series, then you will need a dedicated 20 amp circuit, and the appropriate outlet. I would highly recommend the ATI product as the quality is top notch, and the company is right here in US... everything is made here in good ole USA.
One more thing, the Aperion speakers sound awesome, haven't heard B&W 80x series in a long time, so cannot accurately comment, but if you are looking at budget, you should consider Aperion as they are internet direct, and I think very competitive to B&W.