It's good but not that good.
I can imagine these lenses will be absolutely rediculous on price (and quite rightly so), So unles you have a cool $3-4,000 spare, forget it!
Also, We don't even know what cameras this lens is compatible for. That's the bitch with SLR's .. You get one with the best lenses and accessories at the time, and a year later the greatest thing on the planet could be released with another brand that doesnt fit your camera.
You have to be either :
1. A paid photographer or someone who's equipment is bought for them.
2. Filthy rich and you get one because they look cool.