Personally, I think the Cascadia is the second ugliest truck I've ever seen. The first is ther really hideous International. God that thing is awful.
Anyway, what will these trucks be doing? Drop and hook? Heavy haul? 9 car haulers?
The application might just make all the difference.
I drive a 379 Pete with a 475 C15 ACERT Caterpillar, 18 Spd eaton, 3.59 rears, and can honestly say - don't frickin' buy a twin turbo CAT. The electronics are junk, and have been nothing but problems for 525,000 miles. It's at the CAT dealer right now...again.
Even my boss went with Cummins.