Sorry it took me such a long time to respond to this. There is no, Best oil to put in your car.
They're all really good. Since one of my sponsors is Mobil 1, I'm pervy to that brand. I have 204k SC, so I use 10w30 Mobil 1.
Castro Synthetic, Quaker State, Penzoil, they're all really good, and do the exact same job.
Mobil 1 0w40 is recommended after you've broken in your engine, after 1500miles. It is a cleaner, more efficient oil/lubricant, but most of us have some miles on our cars. I know the New Fords and Hondas use a special oil, and it's possible they're using something similar to 0w40.
As mentioned before, if you have no leaks, you can switch to 0w30-40, but it is recommended that you properly clean and lubs all parts of your engine, before use.
Read up on it.
http://www.mobil.com/USA-English/Lubes/PDS...obil1_0W-40.asp