I work in a large school system as an automotive parts buyer now for 28 years. Before that I was a GM tech. We have a fleet of 850 school buses . We move 90,000 school kids twice a day.We go 100,000 every three days. I've been in oil battles before and what I can see is all oils start out the same. Different brands add different additives or so they say to get different protection. Now the two big problems for oil is dirt and heat. What I have been told by different oil companies is that petroleum based oils hold drit and the drit causes the oil to break down along with heat and metal from wearing parts. Synthetic oils have an ability to keep contaminates from mixing into the oil so it's suppose to deposit more of these contaminates in the filter media and can take higher heat levels. When both oils start out fresh they are fairly equal as miles pile on the petroleum based oil starts to break down were the syntheic holds it's lubricating properties . So with the synthetic oils you have more protection and can go longer in between oil changes. I wouldn't go over 6,000 miles between changes but that's just me. As for the Fram filters I was told by a Fram dealer that Fram wanted to be more competitive in price so they cut the quality in their filter media to lower the price of their oil filters. I would not think this is a good move on their part and would not use their oil filters on my vehicles, now thats just me . I don't know of any failures from this , so to each his own. This is just my five dollars worth you can't get anything for two cents anymore....Bob Yates