I use Schaeffer because it is a good product and I can get it at very good pricing and have it shipped to my front door for free. That is my primary motivation. I don't get caught up in the who is better game. Go for the best value!
Pretty hard to believe but i have seen some of those 5.4 and even the 4.6 ford engines go well over 375,000 miles and still run good. But 1 million and looking like that inside...Um nope!