Besides some of the fictional tracks where it's obvious they hastily put it together with their internal procedural course maker to save time, the real circuit tracks that PD actually spends quality effort in developing easily has some of the best pbr material work and environment detail. It's also still the only sim racer with mostly 3d crowds who also walk about the track too.
GTSport already had some high quality ray-traced static baked lighting which is why the general look in GT7 doesn't look like a significant upgrade, but the move to a real-time day and night system while maintaining that level of quality in GT7 definitely is a pretty big step up.
GTSport also had static weather with 2D jpeg images for the skybox, while GT7 has a full on volumetric 3d procedural cloud/weather simulation system. They're doing quite a bit more than I was expecting for a cross-gen title that also has to run at 60fps on a base ps4. I was pretty disappointed in the cross-gen news at first but am satisfied with what they've revealed closer to release. They just need to get some outsource help in building assets for some fictional tracks for future titles/updates.
With a track like Daytona I think it's reaching diminishing returns while driving. I'm not sure what more you would want out of this track until the move to full on path traced lighting.