I do petco part time.. I am the mentor for the district and one of the top producing trainers for the company. I was THE trainer a few years back, then I left and they crashed my store. GRR I am rebuilding it.
Be careful, Petco classes can be awesome, or can be awful, same for Petsmart. Not all mentors/trainers follow protocol. Petco's protocol is accurate, well thought out, and the trainers that follows it are essentially very good or at least decent. The safe group training and playtime for puppies are often a very good environment. BUT I have caught several petco trainers using prongs, e collars, dominance training, punishment etc which Petco doesn't condone.
You have the right to talk to the trainer, ask about the methods.. If the trainer uses methods that shouldn't be used, talk to GM and report to the DM. I am working on sorting them out in my district right now.
Those classes are def ok, and if you run into one of the better trainers where there is quite a few that are way better than Petco pays them then you are golden. But you have the right to a meet the trainer, ask them so you are comfortable with them.
I recently got a client who had heard of me as far as 4 hours north of where I live, as well as three ours east of me (further out on the island), and a couple of more places. I have people coming from queens, brooklyn, Manhattan to take my classes compared to others. Find THAT trainer in your area and you are good to go. Jus ensure that the trainer understand anxiety in animals (as puppies gets easily overwhelmed) and uses no punishments.