Motor oils have improved greatly over the last twenty or thirty years. Although the results of these test show some companies to be dominant, you must ask one question. How do you drive your car? The car manufacturers have done extensive testing and some warrant their engines for 100,000 miles with current name brand oils which meet their specs (although some require synthetics). I, like Shadow, was a user of Castrol since the eightys and still use it in most applications. It's a good oil and I have not suffered any oil related breakdowns during that time. But I don't drive my car like Jeff Gordon on a Sunday afternoon either. Even when I drag raced motorcycles and cars I used Castrol 20-50. But for everyday street driving, any brand will do. I bought a 1983 Chevy 4x4 with 90,000 miles on it in 1989. The original owner had used nothing but Quaker State in it and had the oil changed every 3,000 miles. I kept using Quaker State in it and sold it in 2002 with 245,000 miles on it. Many don't like Parrifin based oils, but they hold up well in normal,everyday driving. If they didn't, they wouldn't still be in business. Look at NASCAR racing. All the major oil companies are represented. I wonder how many engine failures are a result of oil breakdown? I think they're all good. Some may just be better than others.