I think Forza Horizon 4 was probably the best purchase I ever made, and this was after having played it for a year when I subscribed to Game Pass. I bought the VIP edition too (at a discount).
Mind you, I am rooted in hardcore simming, from creating boot discs to run World Circuit and Nascar Racing to buying Voodoo 3000s and 5000s to run GPL, through SCGT modding to today, owning everything that's been released since except Dirt Rally 2.
I did have Forza Motorsports 7 and I enjoyed it, if only for some of the lesser modeled racing cars from my youth (IMSA classics like the '87 Cougar, RX-7s and XR4Ti's!!). Horizon 4 seems to look better, handles better and runs much better than Motorsport 7. There's a point in FM7 where the car yaws, and you feel the game bring it back, even though you've selected the physics model that isn't supposed to step in. Often it conflicts with you trying to correct it and you end with a tailwagging battle between computer and you.
If this nanny is present in FH4, its hard to notice. And when you're in a purpose-built drift car, it must not be there at all because you can let it hang out. It's pretty hard to spin cars out completely, but it happens. Usually because of the adrenaline of a close battle. There is a steady endorphin drip of rewards and cars and accolades to collect that keep you coming back for more. They make just tooling around sliding so rewarding. I own every car you can buy, have auctioned a hundred more, am sitting on 80mm in game credits and still check in every week. Currently, I'm doing the Lego Champions DLC and as a lifelong Lego fan, it makes me smile. (The sound of crashing through brick structures is extremely satisfying).
Favorite car is perhaps a Sunbeam Tiger modified to about 350 horses with weight taken out of it. 2nd is probably a '73 Porsche 911 RS, lightly modified as well. Just rowing through the gears and ripping down country lanes is so pure and exhilarating. Sure, you can dress up your character if you want. But you can also spend time swapping in new parts and tuning your setup.
If you only want to do GT3 races with pit stops or F1 races with 22 cars, for your own sake go elsewhere. But it if you like the act of driving like I do and you're a bit of a car historian, I can't think of anything better. It would be nice to take these wonderful cars on real race tracks with full fields, and that's what FM7 SHOULD be, but it misses in the handling and performance department for me.
The bad: the music (sucks - just turn it off), having to see other drivatars stupid outfits and their stupid emotes before and after races. The reward system is arcade-y, go figure. You can suck and still progress in the game, but if you have actual talent, you fly through the game.
I use a Thrustmaster TX with the Ferrari rim, a TH8A shifter, and T3PA pedals. Force Feedback is great. I swap from stick to paddles depending on the car I jump into. Just perfect.