Yeah, I've used this lens. It's bloody good! the size makes it pretty damned difficult to handle, but with a
VERY sturdy tripod you can get amazing pictures with it.
The backpack it comes with is also pretty
mahoosive.
p.s. I'll stand by every word said in the Luminous Landscape article.
[EDIT] In regards to the weatherproofing, It has no rubber gaskets on the lens mount, and i might be a
little concerned about the drop in filter slot, otherwise the rest is every bit as hardy as an L lens. I'd be fairly happy with it in a light shower, but if its raining more then a little bit i might be slightly concerned about the said spots. I'd have no worries about the zoom/focus rings at all.
Don't quote me on that though
[/EDIT]