What year? I know you didn't ask about them, but I have always heard the GM 6.0 is pretty bulletproof, even from non-GM guys. The big Hemi is attractive to me, but it didn't do as well as expected in some towing tests. My dad has a 2500HD Ram with the 5.7 Hemi and I have heard no complaints from him about the motor. It feels pretty quick to me, but I have only driven it unloaded. I don't know about the Ford, but the suspension was pretty weak last time I looked at new trucks (2011). They may have stiffened it up a bit. A pretty good review of the gassers is found below.
Review Here 
