Milton is solid when playing average teams; however, when you're used to Hendon absolutely destroying every defense (except GA), Milton seems a bit underwhelming. Big arm, great size, good wheels, but falls short on QB intangibles.
Beck, on the other hand, is a future NFL starting quarterback. Great arm talent, excellent at reading defenses, audibling out of bad situations, great pocket awareness, consistently makes good decisions and can effortlessly make all the required throws.
If you can't get consistent pressure on Beck, he will torch the Vols secondary (and anyone else for that matter).