RE: best oil!!!!
I've used Mobil Clean 5000 10W-30 (and one change with 5W-30) since I bought my truck with 86,000 miles until last oil change which was 102,000 miles and was happy with that dyno oil.
At 102,000 I switched to Mobil 1 5W-30, and so far have about 1,500 miles without any oil loss.
I would vote for Mobil 1.