I love QB Challenge!
In fact, I even have the SNES QB Challenge game!
Young and Cunningham are good, but here's the secret - for some reason Bubby Brister is the best QB in the game. I think the programmer was an Eagles fan and gave Bubby some superhuman football stats to make him good. I loved suckering people into playing against me as Brister.
The problem is that it's sort of like the HR Derby...it was cool in the older days when there were guys you really wanted to see (Sosa, McGwire compared to Young, Elway, Marino, etc). But, the QB's in the league really don't appeal to me in the same way those guys did. It gets a little tired because of it.