I would try an initial trial visit to that groomer to get a feel for how your dog reacts before I would leave them there for grooming. I think you're right about the environment in PetSmart being too hectic for some dogs. We would never take our girl there - just too much going on.
We tried the 'visit' approach with our new vet before we took her in for her first exam so that she could sniff around and feel comfortable before they started poking at her. It really eased her mind, she had some bad experiences at a prior vet so we wanted to help ease her anxiety this time around. She still doesn't LOVE the vet's office - but she is much more calm.