Bryston Powerpac?

I was thinking of upgrading to Bryston 7B ST monoblocks and came across what I consider a great idea: the Powerpac 250. This is what appears to be a compact mono power amp without the usual "big box". These things can be attached directly to the back of a speaker since they have screw holes in a base blate sort of thing, rendering the speaker very close to a powered speaker and obviating speaker cables almost entirely. With bi-ampable speakers, just think, slap on two of these per speaker and you have 500 watts at your diposal... Are they anything close to 7Bs in sound? How much do they go for? The price I can easily get from local dealers. Insofar as some appreciation of the sound quality though, I am sure the dealer will tell me they're great, unless he is trying to steer me to something more expensive or simply to something gathering dust in the shop. I am not sure that they are stocked. If they can be found locally, I will certainly give them a listen. In the interim, does anyone have experience with these?