Beware breeders that don't keep good records. It isn't that they don't care about their animals or aren't breeding responsibly or taking care of them, but not keeping records defeats the goals of breeding--to improve rats as a whole, to develop healthier and friendlier lines. How can a breeding program go anywhere without a "map?" When a breeder doesn't keep good records, that tells me that they are not working on a line, but are simply bringing more rats into the world. They might be great rats, healthy and well-socialized, but the breeder lacks direction.
A pedigree is not a status symbol. It doesn't mean that certain rats are "better" than others. It is a guide, a tool for keeping track of a line and seeing how it has and will develop. A pedigee's most obvious value is one of predicting and planning genetic outcomes. By looking at pedigrees, a breeder can tell what genes his or her rats do carry or could carry. This allows them to find compatible couples and plan lines, not just the next litter, but generations down the line. The heredity predictions go beyond just planning pretty colors. A breeder can look at prefixes, find breeders of ancestors, and keep track of any news about those breeders lines. Do they live long? Have there been aggression problems? What about hereditary disorders? A pedigree allows a breeder to check up on things and know their lines thouroughly--not just colors but the overall rats.
Finally there are more subtle aspects of the pedigree. A pedigree shows how many generations of rats were bred by people who cared enough to keep track of their family. A pedigree shows that two rats were put together deliberately for the purpose of breeding a good litter. "Feeder breeders" and "wholesalers" usually do not have records of parents, because they simply keep males and females all together and let them breed freely, so they don't know who dad is; half the time, they don't even know who mom is. A pedigree will tell you that these animals had NAMES and purpose. They were loved pets. It also can show you how much inbreeding there is in a line and how closely related all your rats are, and that can affect health tremendously.
So, are pedigreed rats "better" pets than non-pedigreed ones? No. But if you are breeding, a pedigree IS important. The longer the pedigree, the more useful a tool it is. Keep track of your rats' families, and get your rats from breeders who keep good records.