I haven't heard of PPRC - but it's not Kennel Club Registration and is likely to be along similar lines to the Pet Lovers reg'n. The parent dogs are quite likely not be KC registered so cannot be health checked to KC standards etc.
You say you've seen these puppies advertised. It's rare that reputable breeders need to advertise as their puppies are usually booked up well in advance.
It's not something I would touch with a bargepole.
Please have a good look through the finding a puppy threads and our FAQs on finding a reputable breeder. If you are content that this breeder meets the qualities CoL supports then go ahead. If not then please stop and think first
a puppy is a serious commitment and it's so easy to go diving in ending up with a lot of problems..