Bought this lens second hand. When I first took it in hands it felt very clumsy. The zoom ring is hard to operate (far from smoothnes of Sigma 18-50 DC EX f2.8) meaning that if you squezze it too much it wouldn't move, but if you hold it right it moves easely. One thing I don't like about this lens is that the front lens rotates when focusing so you can't use polarizer on it
On the other hand it produces quite consumable images that I'm pleased with and I use it more than Sigma 18-50 f2.8 DC EX.
Judge for your self.

All images are 25% resized followed by a 100% crop.

The firs macro I took:





Eagles (300mm):





Macro of a chicken:





Storm breaking: