The build quality of this lens is pretty high for it's price point and it also has a rubber seal on the lens mount. It feels substantial compared to the Nikon, but the latter isn't built so bad as well. The focus and zoom rings are not as smooth as those on the more expensive lenses, but they felt somewhat the same as the ones on the Nikon's 70-300VR. As expected, the lens extends when zoomed in and out, the front part does not rotate so your CPL filters will stay in the right orientation everytime. The impressive lens hood is made in The Philippines, which is good since buying this lens supports the people and their families working in that factory.
This lens is generally believed to be sharp and the VC works better than Nikon's own 70-300mm VR. The focus distance is also closer on this compared to the Nikon I was told. The CA on Nikon's 70-300VR is very strong and noticeable, while this lens seem to handle it better. The lens looks amazing from f/8 or f/9, wide open it looks sharp but stop it down by a stop and you will notice a huge difference in sharpness.
Out of focus characteristics look cheap but not offensive, as expected from a lens of this price and class.
This lens takes 62mm filters and I simply use a step-up ring with it so that I can use my 77mm filters with this lens. The problem is that I cannot use the lens hood when I have 77mm filters on this which is not so much of a problem since I would use a circular polarizer with this most of the time anyway. If you want to use this lens with it's hood and still be able to use CPL filters then you would have to drill and file a hole underneath the lens hood so that your finger can fit it into the hole and adjust the CPL with it, I did this before with the 70-300VR's and the 80-200 f/2.8D's hood.
The VC on this lens works very well, I can handhold at 1/15s to shoot a waterfall in poor light. I even shot a famous wooden cat sculpture with it at 300mm with 1/8s, check the images at the end of the commentary. The autofocus hunts a bit and needs some improvement but this is not a problem for my intended use for it, which is a lightweight landscape lens. I believe that the AF is decent enough to enable you to shoot some sports in a good and sunny day but do not expect it to perform like a fast f/2.8 lens.
Generally, people who would like to buy this lens are landscape photographers or people who want a cheap alternative to the 70-300 lenses from Nikon or Canon. This is a light lens with a long tele range of 70-300mm and is very useful in shooting waterfalls from a distance so you would not distort your subjects with foreshortening and perspectives. I also believe that this is good enough to work as a decent portrait lens in a studio using strobes, shot from f/9 and above, this lens looks good.
Pros:
+ lightweight
+ very good for the price
+ nice build
+ good VC
+ generally sharp
+ weather sealed
Cons:
- not a fast lens
- AF hunts in certain situations
- cheap packaging(insignificant)
Overall:
Amazing lens for the price, this is a very highly praised and recommended lens.
I would certainly recommend this over Nikon's own 70-300VR, I have no idea about the Canon version but reading through the articles on the net, people have the same general opinion that I have shared.