At the end of last year, using exactly the same dataset I did reports for an IT customer. To the staff I showed that things were improving and by a high-rate -- moral buster. To the management I showed some areas that required drastic improvement if they didn't want to go out of business.
IMHO, Norton is not better than some you listed, but are rarer and have a better supply chain. The fact that you can buy good-fitting, quality parts for them makes them much easier to rebuild but there are way less of them than others. In most things collectible, the rarer, the more valuable.