I have used both Performance Auto & Magnum collision.
I would go with Magnum hands down.
I have used Performance Auto 2 times and both times I had paint drips on my wifes car. First time there were 2 drips on the chrome trim around the windows, I did not pickup the car so I did not see it till about 2 weeks after they were done.
2nd time (thought I would give them one more go) they left 2 large paint drips, one of the bumper (about the size of a small fist) and the 2nd on the lower passenger door (some of half dollar coin). The trunk also does not seat as it should, makes a nice cluck sound, very different then it did before. Again, I did not pick it up and did not see the car till about 4 weeks after it was picked up (little to late to b*tch about it).
The wife then got into a 3rd accident (all repairs were for the rear end) and we took it to Magnum. This time I was going to pick it up and have a really good look at it. When I did pick it up, I could not find anything wrong. The guy I talked to asked where I had the previous work done because he notice they didnt do a great job and cut some corners, and I believe it.
The funny part about this is when I tell some my story about Performance Auto they will say "they usually do good work".