I stopped using Petsmart last year because:
1) the one groomer I trusted there left and
2) I saw a guy grooming a small dog who got angry at the dog for moving around. He yelled at the dog and grabbed it by the collar, kinda jerked the dog, put his face right in the dog's face and fussed at the poor thing.
Now every time I go to Petsmart I look for this him. The really bad thing is a girl at my work takes her dogs to him! She swears he is wonderful.