I have a very unscientific way of deciding. My last dodge was junk. I bought it new and owned it for about six months. During that time the paint peeled off of it and the company refused to do anything about it because the warranty was for "rust through protection." The wiring harness burned up on it (warrantee) and the transmission started making a lot of noise in first and second.
My last new truck was a 2006 Ford with a 6.0 Engine. I've spent more on that engine than I paid for whole trucks. I had issues like a blown head gasket and two burned up FICMS that ford should have covered under warrantee, but refused to. I had the whole top end of the engine redone two years ago for $8600 and it had to be redone last month for $7000 after a cam follower failed and bent valves and pushrods and left metal shavings throughout the engine. My complaint is with the engine AND the way Ford treated me when I tried to get it fixed.
After I get done paying off the $7000 I just put on my credit card, I will be looking at a Chevy or GMC.