Sunfire Cinema Grand or Earthquake Cinenova?

Are these amps as good as they look? I am kinda stuck right now. I own a Bryston 4B-ST. To complete the home theater I need to purchase another 3 channels (6B-ST). Or, I could sell the Bryston 4B-ST and for around the same price as the 6B-ST I could get a used Sunfire Cinema Grand (Signature?) or the Earthquake Cinenova Grande. From what I've read, they seem to have impressive numbers, but will they produce the goods? I do not have the ability to audition any of these amps. I need an amp that can produce the goods into low impedance while at the same time do justice quality-wise to my speakers, I am driving B&W Nautilus 804s and HTM-1 center. Right now I'm having to limp along with an Acurus 125x5--a good amp, but not able to deliver at higher volumes. Help would be appreciated. Thanks.