The car models in Gran Turismo 7 are second to none. No other game has every car detail down to a T like GT7 has, none. And this is probably going to be a great sell for those who play with a VR headset. The sounds of the cars are also very true to real life, this from the outside views, for the vast majority of them, only a few oddities here and there. The cockpit sounds however are really amazing, and it's again, another great sell for whoever is going to play in VR.
The Online mode, while not what I play normally, and with still a few issues needing a fix (the way penalties are dealt with, needing more daily races with different categories of cars), is still one of the best you can get on a simcade, if not the best.
The Photo mode, is also second to none. Also not my thing, but I did try it a few times to make my own pics of cars I like in fitting places, and it's really incredible. Probably the best out there.
The game is incredibly controller friendly. It's probably the best racing game among the simcades or above, that can make a person who uses a controller, almost as fast as someone using a wheel. This for me has been one of the best things of any Gran Turismo to date since I don't have the space or the money to spend on a decent enough wheel setting (plus I play other games other than Gran Turismo so the wheel can't be in the same place 24/7 unlike what most hardcore racing gamers do).
IF, you are a mostly single player/campaign completionist type of player, then I suggest you wait until either Forza comes out, or even until 2024, because this game is lacking massively in that department in many aspects. OTHERWISE, go for it 100%. Especially now that it's at 40-50€ on most stores (physical disc) so it's a very justified price point unlike the 80€ at launch.