Bryant Dunivan 111417 posted:… I'm not in a rush, but want to get the best smooth side cars available. Something along the lines of Lionel # 6-15326. They look nice, but scarce. …
The Visionline Niagara is a scale engine, and the Lionel cars are not (shorter than scale by 3-4 inches). Also, the Lionel cars are generic while the GGD cars are closer to prototype. That said, the Lionel cars are nice and to many they look better on tighter curves, even your O72 curves, then the longer GGD cars.
I have similar passenger cars from GGD and Lionel in Pennsy colors. On my old layout, which did not have the greatest O-72 trackwork, the Lionel cars ran better. However, I really like the look of my GGD cars especially behind my larger engines such as my scale T1 Duplex, Centipedes or E7 ABA. A lot depends on what you want.
If you want the GGD cars and are using high-rail track, I would go with the 3-rail models. You can close the gap between the cars by going to Kadee couplers, but that is a different topic.
ADDED: I need to type faster - I see others have already made similar comments
