More power for better sound at low volumes?

Hello All,

I'm wondering if a more powerful amp will provide better sound at lower volumes, all other things being equal. For example, my Jeff Rowland Concerto is rated 250 into 8ohms and 500 into 4. A Bryston is rated 300 and 600. Does that mean I could get better low volume sound with the Bryston? If not, what is the secret to better low volume sound?

As usual, thanks in advance!
rustler