I got some from Amazon when they had a rebate, and Amazon had a really low price. Pennzoil full synthetic 5W-20. It seemed okay.
I'm fairly confident that any major name brand, or store brand from a well known store, which labels the oil with the API starburst, donut, & GF rating is useable. Useable for me.
Some high end oils have better better grade base stock. Sure, I acknowledge that even though I can't tell the difference, there is a difference between group II, group III, whatever oil. And I trust that some oil formulations have different additives in different amounts, However, I don't have a high performance car. My thinking is that any modern oil with SN, SN Plus, and GR5 rating will be good enough for my car, as long as I'm changing the oil frequently.
As motor oil is such a hot button topic, I'm open to anyone else's explanation of TBN, Moly, Boron, et cetera.....and how that will benefit this little naturally aspirated 2.5L Duratec. I'll probably still buy whatever is on sale, with a coupon, offering a rebate. It's all brand name oil. Even Amazon.com oil & Wal*Mart oil are able to meet API & GF specifications. And I can't think of any over the counter, name brand oil, which will not meet Ford specification.
In my youth, I spent more money. A lot more money. I used boutique brand oil. I can't tell if any of those oil formulations had a long term benefit to those cars. I do know, that without a doubt, when they claimed that the oil would yield better mileage and more power - I did not see it happen. Royal Purple, Red Line, and Lucas Oil did not make a Honda Civic faster.