All these engines are good
Ford V10
362 @ 4750 rpm
457 lb.-ft. @ 3250 rpm
Vortec 8100
340 hp at 4200 rpm
455 lb-ft at 3200 rpm
Vortec 7400
290 hp at 4000 rpm
410 lb·ft at 3200 rpm
It all depends on how much weight you need to move it's that simple. A short light class A will be a rocket with the 8100 or V10. A heavy rig will eat all that torque...and gas
Can't speak for the engine life of the Ford but it must be good, for the chevy I run a Vortec 7400 with more than 110,000 miles and it purrrs and is very strong.
At an equal price I would go for the Ford simply because at least in my part of the world Workhorse parts availibility is poor and much more expensive than a Ford.