Post 2009 main reason the frame. While I am not bad mouthing the pre 2009 frame the newer frame is an improvement.
2012 and newer 103 is standard with ACR just makes sense.
Try to find a slightly used '14 SGS, better color options than the '15's. The Rushmore bikes are hands down the best design and will depreciate less than previous years.
X2. The new Rushmore bike are awesome. My 14' can turn like a sport bike. The new frames wheels and brakes are awesome.