Actually, I picked up the wrong weight by mistake and that prompted this post. I think I will take it back and pick up the recommended weight. Maybe at 10,000 miles will go ahead and switch to Mobil 1 anyway.
Personally, I use AMSOIL synthetics. They have three grades (prices too) to choose from. They range from 7,500 mile oil change interval to 25,000 mile intervals. Cost is a lot less when you consider the less frequent change of oil. Second, and most important is that this synthetic formula reduces friction and therefore parasitic loss, improving fuel economy in the 5% to 10% range. Worth it for that alone! Also good on cold start. More oil on the top end than conventional oil.
Oh yes, I sell it too.