I talked to the Pennzoil engineer who took apart the engine in the Million Mile Truck (Chevy Silverado) that the company bought from the owner. He had a newspaper delivery route in Georgia (I think), and he religiously changed the oil in the truck. (That's how Pennzoil got in the picture.) The engineer told me that every part of the engine was still within specs. There's something to be said for taking care of your equipment. (The owner had replaced the water pump and the alternator several times, so some things did wear out.)
It won't take long to attract those guys complaining about one brand versus another. Truth is that all companies push their vehicles off the assembly line as fast as they can and not all of the are put together like they should be. A friend of mine worked for Ford for some years and had plenty of horror stories about using parts that weren't 100%. If your vehicle is a lemon, your best bet is to get rid of it and move on. (That's easy to say, but it's a huge investment and not always that easy.) I had a GMC with over 350K miles on it and the engine was still going strong when some girl decided to run a red light and destroyed it. I replaced it with a Ford because the electrical system in that GMC was a nightmare. I'm on my second F150 and couldn't be happier.