I've been the differences in actual engine wear, not concerning engine cleanliness. I know that synthetic oils will slow internal engine wear, therefore, I use synthetic oil in anything I can.
I'll use one example in particular. I have a customer that owns an 8th Gen Corolla, well known for their oil burning at a particular point. He changed the oil on that car religiously, every 5,000 miles or sooner (depending on time, not to exceed 6 months). At 160k miles, he had a severe oil consumption issue (1 qt/500 miles) and so we replaced the short block. What we found upon teardown was that the engine was one of the cleanest we'd possibly ever seen inside, just using regular dino oil and a Toyota filter, but at this point, you could wobble the top of this pistons in their respective cylinders, they were literally egg shaped!
Comparing that to one of our employees that has a 2AZ, another engine known to have oil consumption at higher mileage, he has used nothing but full synthetic oil in it since day one and has zero oil consumption issues to date (over 100k miles at this point IIRC).
There's a lot that goes into oil and I'm one that has a great amount of respect for those products of high quality, as are many here. Do we over think a simple purchase of oil? Sure! But isn't it satisfying to have that peace of mind knowing that you probably won't have an oil related engine failure or premature wear because you spent the extra time to learn the details on what goes in and how long to keep it going?