I posted this over on clio197 but worth noting before deciding which version to buy:
And taken from the comments on that video:
- The Game runs at 720p 30FPS on Xbox 360, Xbox One is 1080p 30FPS
- The physics are much better/realistic on the Xbox One version compared to the Xbox 360 version (Xbox One uses the Forza 5 Physics but they made it a little easier but not too easy, still feels realistic with all assists off, Xbox 360 version uses the same Forza Horizon 1 Physics which weren't all that realistic, they were still ok though)
- There is no weather on the Xbox 360 version
- There are no car meets on the Xbox 360 version
- Xbox one has 220 cars right now, Xbox 360 has 197 cars right now
- There is no tuning in the Xbox 360 version
- There are only 500 events on the Xbox 360 version, Xbox One has 700 Events
- The cars are fully detailed and remodeled on Xbox One, Xbox 360 only has ported cars from previous games
- There are way more loading screens on the Xbox 360 version (Obviously)
- There is no grass on the Xbox 360 version (meaning there is no Foliage System or whatever you wanna call it)
- Multiplayer has no traffic and only 8 players on the Xbox 360 version
- This is only a rumor but there will not be any DLC for the Xbox 360 version (RUMOR)
- Drivatars are not on the Xbox 360 version (Obviously lol)