There are a few key differences between the John Deere 5 Series and 6 Series. The 6 Series is a newer model, so it has some updated features that the 5 Series doesn't have. For example, the 6 Series has an updated cab with more space and better visibility. It also has a more powerful engine and stronger hydraulics. The 5 Series is still a great tractor, but if you're looking for the latest and greatest from John Deere, the 6 Series is the way to go.