Easily the biggest worry when changing tyres is the risk of them getting scratched.
I took my A3 in to a place I've used for years and expressly asked them to be careful.
Two minutes later the young lad came out nearly crying, holding my ruined alloy.
Never went there again but they fixed the wheel.
I actually would make that a place
I did go to again. He was honest enough to come out and tell you and that goes a long way in my book.
I actually had a Vauxhall main dealer (who have since lost the franchise) who took chunks out of one of my 19" Astra VXR alloys and they just tried to cover it up. One conversation later (which included the words "I'd like to speak to the dealership principal") later and 1 new alloy on the car.