Who Chose the 300 f4 over the 100-400 for Birding and Why?

I chose the 300 over the zoom for a number of reasons:

1.  I already have a wide range of zooms: 90-250 f2.8, 50-200 mk1, and the 75-300 mk1. These zooms already cover a why range of circumstances. The 50-200 is a good all around mid length. The 90-250 plus TC14 was my bird lens before the 300, as well as an excellent outdoor event lens (bullfights, rodeos, windsurfing, speedboats, bicycle races, etc.  For these large moving objects, I always got a high number of keepers.  And since I zoomed in the field and relied less on PP cropping, I maintained good image quality. Of course, there has been a weight penalty, and I always used this big beast on a tripod. The 75-300 is just ok from an image quality standpoint, but if one really wanted to capture an image with little weight, this does the job. So I already have good zooms, one light, one heavy, and one in-between.

2.  Image quality was rumored to be excellent...and this lens does not disappoint!

3. Combined in body and lens stabilization systems...just incredible.  Since all of my bodies are Olympus, this makes sense.

4. It is lightweight!  I know, there are a few out there that think it is a heavy lens. if one is in reasonable shape, this lens is easy to carry in a side holster. Come on guys, our tiny dachshunds are heavier, and my petite wife carries two of them. Granted, I am above average as a 67 year old that has led an active outdoor life, and most people these days work behind a desk.

5. Despite what some have said, the bokeh is just fine.  Of course with any lens and compositional setting, isolating the subject is just part of photography.

6. Lens speed.  A lot of bird photography is done under less than perfect conditions (see photo above).

7.  Having said all that, the 100-400 seems to be a great lens as well.  We are fortunate to have two excellent long photos.