For me, if the grip becomes extremely high, it feels more like onroad with jumps than offroad
- this is usually only the case indoors on carpet (like the EOS).
I really prefer outdoors - most indoor tracks seem to be ill prepared to keep your car intact in a bad crash (A concrete floor that is left exposed, walls at the end of a straight that don't have any damping structure on there to prevent broken shocktowers, sharp edges, hard barriers and awkward places to get your car stuck or break your car on, etc) - the lighting isn't good enough for the best action pictures, and there are a couple other reasons why to me outdoors is superior - even when that means you'll have to completely rebuild your car because the clay is stuck everywhere!
I think I also feel most at home on dirt/clay and wet astroturf
My car, setup and me as a driver just seem to work better as the surface requires some sliding!
That said, it's all good fun, and indoor tracks are the bomb when the season is not suitable to run outdoors
But when it's above 10 degrees and the track is not covered with leafs, snow or a flash flood, I will pick to drive outside any day!
(This leaves me to conclude it might be cool to have a retractable (stadium) roof over a track)