You're not thinking this through...
You and all the other people think 6.0 are trash and sell them for super cheap. Buying cheap allows you to put some money into it, make it reliable, and tailored to your needs. You then get something that is solid, capable, and purposeful.
If you go GM, your paying more up front, and then there is no room to tailor to your needs. You will forever be nickeled and dimed to death fixing stuff that should have been addressed when you first buy a money making machine. At that point you are just throwing good money after bad.
When you buy your 6.0, let me know. I'll tell you how to make it the best truck you will ever own.