But then again, have you ever seen the marketing people say "this lens is soft"
What about the 135/f2.8?
I'll join the chorus of those curious about this lens. My 400/5.6 has a pretty bad fungus problem and is on the fast track to the bin. With no modern Canon replacement in sight, I can't wait to read some reviews on the Tamron to see if it is a possible replacement.
My only concern is that the length of the lens seems short given the focal range covered. Now I'm no lens designer, but I've always believed that the more "tele" a lens is, the more advanced (and expensive) internal optics that are required to produce great results. Hopefully, Tamron will prove me wrong.