There are sooooo many horror stories about petco and petsmart grooming. Mine is no different, there have been many threads about them. The first time I took Teddy it was okay, they just did a trim. The second time they told me he was "matted" on his belly and they just about shaved him there and everywhere else was just so horribly uneven. This time I took him to a real groomer and she begged me not to take him to those places anymore. She told me that alot of dogs end up traumatized and hating to be groomed because its like an assembly line: one person does their bath, someone else does nails, etc... and they don't take their time and they are NOT gentle, especially if the dog doesn't like it.
Save yourself the heartache and go to a regular groomer right from the start