what are the different tones of alto sax facing and reed combos?

what is the sound difference in a closed mouthpiece with a hard reed
and and an open mouthpiece with a soft reed?
(I want to know stuff like brightness, volume, bendability, etc)

the reason why i'm trying to know this is i'm going to get the Runyon
Jazz alto sax mouthpiece and I'm trying to get a really good big band
jazz sound

Thanks