On the surface a ton-and-a-half chassis is a ton-and-a-half chassis ... so a Chevy 4500 should "equal" a Ford E450.
However ... it's that superb Ford V10 with it's high shaft torque, reliability, ultra-smoothness, and other characteristics that sells me on the Ford E450 chassis. Up to this point good old Chevy V8's are fast becoming a dinosaur ... Chevy needs to upgrade their line of engines. Ford is obviously pouring a lot of engineering resources into constantly improving their engines. GM needs to get on board.
P.S. Ford's E450 cutaway van is also shorter than Chevy's 4500 cutaway van. This is why the Chevy cab has more leg room due to it's doghouse being further forward - hence a longer outside hood length. For those of you who want the "shortest overall length possible" for any size Class C coach - the Ford chassis has the Chevy chassis beat.