My personal experience from Lu's Auto Service Car.
I came to Lu's for car oil change last week.I asked for mobil 1 oil ,Mr.Lu's said it cost $ 20.00 more and the total cost would be $ 50.00 for mobil1 oil change. Well today i was curious about my oil so I just took a look at my oil and found it pitch black and dirty so i'm not sure if he changed my oil or not. I took my car to 2 other auto shops and asked the machanics to come out to check on my oil. They said that my oil is very dirty and needs to be changed. I only used mobile1 oil for my car and it lasts up to 5,000 miles. I only drove about 300 miles for 1 week and it's already needs to an oil change again.
My lesson is that you should never trust a mechanic unless you know that they're good.