Upfront in what they think needs to be done. No reasons to take the car back.
I have a BMW X5 and the car just wasn't running. I wanted to find somebody that could do a good job. The car had 115,000 miles on it, so I was looking to either get the job done properly or sell it and buy a new car. I saw an ad in the paper advertising Holland Service as an alternative to a car dealer, so I talked to them.
They were upfront about what they thought needed to be done. At the end of our discussion, I agreed on a price and they did the work. They didn't try to negotiate to get a higher price, and they finished the job when they said they would. I have no reasons to take my car back. It runs beautifully now.