We’ve had this discussion several times before. In the past, when all full size GM cars were “cookie cutter” the same, the reliability figures came is as 1. Buick, 2. Olsmobile, 3. Chevrolet, and 4. Pontiac. There was a significant difference between virtually the same cars. Why???
It turned out the use and type of driver these cars were exposed to. Buicks were bought by older, more conservative drivers, Oldmobiles by “Dick Van Patten” family type drivers, Chevrolets were most used for business by salesmen and as company cars, and Pontiac sold … ATTITUDE and PERFORMANCE!! My son worked with a typical aggressive Pontiac driver and this guy’s car, a Pontiac, was constantly being fixed.
All in all, I use the CR ratings to ferret out the solid black items and avoid cars so rated.
The recently developed ratings by True Delta tell you a lot more; they give you visits to the shop, cost of repairs (not regular maintenance), warranty repairs, and repairs per 10,000 miles or so. The findings parrallel those of CR, but are more timely (quarterly) and allow the user to judge the severity of those repairs.
Used together, I find them very useful.