This is one very impressive lens. Light weight, fast to focus and sharp. The IS is something to experience. It was late in the day and light was fading fast. This shot was taken at 1/40 sec at F / 4.0 ISO 400, 200mm. Depth of field is shallow and I focused on the eyes.
The fact that you don't have 2.8 is obvious and the lack in speed is a concern, but the size and weight makes up for a lot. The lens feels right and the view finder is very clear.