I have been running Dello 400 15-40 oil for a long time and decided to change to Rotella synthetic after seeing unusual wear on my cam. I have 60 hours on my bike and I change my oil every other ride so I am very familiar with the color of the used oil and also how much metallic sludge is on my magnetic plug. After switching I was surprised to find that the used Rotella synthetic oil still looked like the day I put it in and my magnetic plug had very little metallic sludge. When I ran the Dino oil I would always have a good amount of metallic sludge on the plug (a little less than a sixteenth of an inch build up) and also the oil would be very dark. So what am I saying? Well, nothing scientific, just my personal observation. I am not bashing "dino oil" just wanted to give you my real world view and experience.