I played the free demo and was really turned off with how menus worked, loading times, and just the general feel of the game. This is coming from someone who owns every Forza game released. Forza 5 wasn't bad, but compared to what other racing games offer these days it felt sparse.
compared to what other racing games offer these days, forza motorsport is king
go drive a fast car on the ring and return here to tell me otherwise
general feel of the game is so greatly improved in 5, that if you go back to 4 it seems ..simple.
then you have the laser tracks and the better physics and sound etc etc etc.
and they managed to do it day 1 too.
plus,
whatever you see here in horizon, it simply would not exist in this beautiful state without t10 providing the engine, cars, physics etc
so pay respect where you have to.