4 is my least favorite Forza Horizon, but it's still good and worth adding to the collection. I'm not a fan of the seasons and how you can't change that yourself instead of waiting a week in the real world. Not to mention some stories or challenges will be tougher to complete when for instance roads are covered with ice.
The main map is also too bland for my taste, Fortune Island DLC map is way better with all of the twisty roads and cliffs... if only they made it bigger.