I am coming off a Nikon, latest being a D300. I could NEVER afford nor carry a 600mm Nikon. Key advantages. 1. Getting bird and other nature shots not previously achievable. Don't underestimate this point, a good quality shot is better than an outstanding quality shot you couldn't take. 2.
Compact; lightweight; fast focus; afordable
Image quality a bit soft at 300MM .; but for the price