Hey Guys,
I've honestly haven't ridden the bike enough to give a balanced opinion, unfortunately winter has settled in here in Ontario.
What I can tell you from my initial experience with the bike, is that it has yet to have left me wanting. Whether I was in eastern single track (80% of what I ride),or on submerged corduroy, or on loose pack fire roads, the bike performed flawlessly.
In my opinion the 450/570 are identical machines, the only difference is power delivery. I would argue it is impossible to be unhappy with either of these machines, they are the pinnacle of off road motorcycle design, and we are truly living in the golden age of motorcycling.
The bottom line is, will you use / benefit from the extra power of the 570. I come from a road racing / motard back ground, so I find the 570 highly entertaining when the terrain opens up, and I do not feel it handicaps me in close quarters.
Here are a few of my observations to date with the 570; its an absolute rocket (throttle wheelies on command), the fuel injection is faultless, feels like a 250 once rolling (no BS), looks sooo much better than a KTM, best sounding stock exhaust I've ever heard, tail piece resembles Aprilia RSV4F (a good thing), and did I mention its an absolute rocket???!!!!
I just purchased the map switch for the bike, so I'm looking forward to a little experimentation in the spring, hopefully it will only improve what has already proven to be an extremely capable motorcycle and put the 450/570 debate to rest.