Panzer Dragoon Saga I would put right up there in the pantheon with the N64 greats - Mario 64, Zelda 64, etc. And NiGHTs isn't far behind.
In 96-97, the N64 was clearly the better system. The 3D was much smoother than the Saturn, which was really important back then. The N64 had some blockbuster single player games everyone was talking about, and two of the best multi-player games of the time. The good Saturn games were either obscure and hard to get, or stuck in Japan.
Looking back now, the 3D games on N64 mostly just look ugly, and the early 3D controls are very clunky (minus a few standouts). The N64 library has really lost its luster. Now with the Internet, it's much easier to find out about, and get your hands on great Saturn games that would have been amazing back then with a little more promotion (Powerslave I'm looking at you).