10 out of 10 points and recommendedIQ, AF function, silence, constant length.A bit heavy.
First: I am not a pro, have not even photographed much. Still, after some experience with a cheaper 70-300 zoom, and after first thinking of a zoom reaching to 400-500 mm, I am now happy that I bought this one.reviewed September 8th, 2008 (purchased for $1,225)
Before deciding, I carefully went through all the test information of the possible alternatives.
Also in practice, the image quality does seem to overcome what I could have gained putting my pennies in image stabilization or longer reach.
With my Nikon 300D:s 12 MP APS-C size sensor, pixels clearly are the resolution-limiting factor.
A good quality TC, in my case Kenko Pro 300 DG 1.4, gives extra reach up to 420 mm, and this glass really seems to tolerate it.
Technically the tube works smoothly, accurately and silently, and is a joy to work with. Extra convenience comes from its lenght staying invariably the same.
I hesitated about the lacking stabilisation.
Now, the objects, like birds, often move fast, so a short exposure time is needed anyway, (and the 300D with its good high-ISO area allows it).
And with a tripod, stabilisation would be off.
So the only thing I could think of -I don´t actually miss it.