Hate to be that guy, but did you even look at the first page of threads before you posted this question? There is a specific thread about the 6.7 about 9 threads down from this one.
There are a plethora of topics about diesel vs gas, Powerstroke vs Cummins vs Duramax, 3/4 vs 1 ton, newer diesels vs older diesels. There is literally more information in this very sub topic than you could ever want. You could have instant gratification by reading those threads as opposed to asking a very general question to start a new thread.