Parasound A21 vs Bryston 4bsst 2

I'm looking for any information regarding the Parasound A21 vs the Bryston 4bsst 2. The amp will be used to drive a pair of Aerial 7Ts. It's not about what's better, but what one represents the better value, considering the cost difference. In other words, for those who say get the Bryston, is it twice as good as the Parasound? My room is 20' x 26', I listen to contemporary Jazz, and my priorities are soundstaging, imaging(front to back placement), and as close to neutral as possible without brightness. Thanks in advanced for your opinions.