The FreeStyles are expensive. Basically the top of the line for their long track set up. All the best shocks and suspension. Stonger a- arms etc.... If you just tool around in off trail, you don't need one. The Summit's work very well. Kind of the same as the difference between an Assault RMK and a regular RMK. I don't know that the Freestyle comes in a 600 version. Likely only 800. If you are a serious mountain rider, I think bigger is better. If you are just riding around the UP hills, I'm sure a 600 would be fine.
The FreeStyles were sno-check only. You won't find them out there now, unless someone is selling, or a dealer somehow got their hands on a left-over or a no-show.