"Fast standard zoom lenses are certainly a hot spot in the product portfolios. So far this arena has been dominated by the original manufacturers although the third-party manufacturers tried to challenge the big boys every once in a while. Tamron did so as well with the SP 28-75mm f/2.8 XR but the lens had/has no differentiator other than its low pricing. As such it was popular among amateurs on a budget but it has been largely ignored by professionals. However, their latest offering is a different beast altogether - the Tamron AF 24-70mm f/2.8 SP Di USD VC. Other than matching the specs of competing products it has something unique - it is the first fast standard zoom lens featuring an image stabilizer (VC = Vibration Control). An ultrasonic AF (USD) as well as weather sealing are also part of the package. Obviously Tamron is pretty much convinced of the capabilities of their new baby because they do no longer want to compete by price - they are asking about 1100EUR/1300US$. Now this may still be "just" half the price of the new Canon EF 24-70mm f/2.8 USM L II but it is a magnitude more expensive than the old Tamron AF 28-75mm f/2.8 XR and it's certainly no budget item anymore."
Via Philippe Gassmann