I agree it all depends on the staff and the service centre. I had new tyres put on mine, and they damaged one of the wheels. They owned up to it and got it repaired, however afterwards it didn't match the other three wheels.
I told them I wasn't happy and so they got all four refurbished, it was a good win for me as 3 of them had a bit of kurb rash. Now all four are perfect and the colour matches the car better (the original colour was too silver). I know my normal tyre guy wouldn't have been able to afford to do this. They also did a Hunter alignment on the car for free. So in the future, even though they mucked up initially, they made up for it with their customer service.
Throughout it all, they made me feel valued as a customer and never once did I feel like they weren't going to solve the issue. So even though I never thought I would say it, I would recommend Kwik Fit, at the very least for tyres.
Like anything though it can be luck of the draw, and perhaps some people would say I had a bad service seeing as they damaged the wheel originally, I guess it depends on how you view it!