Picked up a canon 300mm L this week. The 300mm is to give me the reach I need w/o using a TC with my 70-200mm I’m also toying with the idea of going all primes, so this is my first step in that direction. It was between the 300mm and the 100-400 zoom, but the speed of the 300 at 300 won (f/4 -vs- f/5.6 with the 100-400). Also it’s smaller and lighter. So far I’m very impressed with the IS this lens has. I’m able to hand hold a 300mm lens at 1/15th of a second with zero camera shake. Pretty impressive. It’s also very sharp wide open.