I absolutely love the 90mm. Try it and do this. Place camera over your right eye. Open your left. Suprise, no real distortion... just a floating frame around what you may want to shoot.
This is great for following fast action, as you can see the action without all the distorton. Kep track and move the camera in.
Now as to quality? Color, contrast, sharpness, all unreal. Very nice.
Mine is always on my belt (as is a G1 with a 35mm or 28mm).