We used Chips Away for a parking scrape down the sid of our Pacific Blue Mazda 6 (Scuff caused by my dad's inability to reverse in a straightl line on his own drive watched by his own CCTV system

)
They ended up painting the car twice on the day quoting £120 to sort it. The first time there was an apparrent reaction, looked like the spraygun ran out of laquer and air blasted the wet laquer.
After they removed their work and tried again the paint match was about as wrong as you can get without it being red!
They then, some days later, took it to their unit and still cocked it up, dull, bad match, tons of ovespray.
They ended up paying for a local bodyshop to put it right. Still cost us our £120.
The leson here is they are called "chips" away, dont use them for anything bigger, or they'll make your car look sh*t.