I've used both Prestige & Staithes over the last few years and I prefer Staithes.
I used Prestige when my car was still under warranty and some of the work carried out has been poor and needed re-work (gearbox oil leak after flush, exhaust not fitted correctly after a cat replacement) , I was also told I needed 'brakes all round' when the current ones only had around 25% wear (didn't find out until I bought the parts to do it myself and took the wheels off), anything that requires the star computer seems to be a problem too, but the last straw was when I was told the head would need removing and the valves needed 'cleaning' when my car lost power (turned out to need a catalytic converter failure).
Staithes on the other hand do not look anywhere near as good (workshop small and tucked away) but their quality is very good and he knows his way around the star computer very well, I'll be getting my gearbox oil changed there in the next few months so it will be interesting to see how that compares.