Ignore the Forza fanboy
First of all, I own all the Forza games including horizon so can offer my view on this game with no ties to either side.
I love this game. Being set within a city is great. Really dangerous driving. The autolog is great and I love seeing my friends faces on billboards around the city showing how good they are. Being chased by the police is also awesome. The whole game keeps your heart pounding and it feels like a better version of burnout. The races aren't impossible. They are very well balanced. I cannot put this game down. Everytime I get in from work, autolog tells me if a friend has beaten any speed camera speeds, race times, longest jump etc. Then I am straight back on it to beat them. Yep Forza horizon edges the graphics side with it's attention to car detail and locked frame rate. However, nothing beats the city of fairhaven and it's team of police interceptors. Go anywhere, be anyone. Race your way.
This is a must buy