In my opinion both look good.
My main issues with grass splines are:-
- up close you can see that they are splines (e.g. near the road junction in the top image)
- many, especially the older ones, do not have LODs but the few from Toxa_Batoxa that I checked do have them
- it is not possible or practical to customise them to suit different circumstances
Grass splines, in my opinion, are best used closer to the track
I prefer to use TurfFX (but avoid conflicts with roads, etc) and PBR textures.
The big advantage of TurfFX assets is that you can customise them (i.e. adjust heights, density, stalk thickness, flowers, etc) to suit plus they are animated. Close to the track I prefer to use Clutter Effect assets because they combine stones and other "clutter" with grasses (which are still animated).
I have stopped using all non-PBR textures because, appearance-wise, they simply cannot compete and they do not play well with PBR textures. PBR does have some issues which can be worked around (and one of those issues, the "jelly fish guts", has reportedly been eliminated in the new HD Terrain that is coming).
My thoughts.