I bought my Xbox 360 as a media center, and to play PGR 3/4, Forza. I still have my 360 and could've continued using it as a media center, but I bought an Xbox One just to play Forza. Horizon started out as a great series, but I think they need some new material. The game looks amazing, but it gets old really fast (especially if you just have the base pack). They did good with the Blizzard Mountain and Hot Wheels DLC pack. Even the regular Forza Motorsport series gets really old as well. I like the selection of cars, but their upgrades are very disappointing.
The other problem I have with Forza is the overall experience is really expensive. I preorder the games, and I pay about $110 for the ultimate edition. Add on top of that the fees for DLC's...I'm glad for Play Anywhere. I don't have to purchase an Xbox to play Forza anymore.