Summary: I have the Nikon 18-70 lens and the HB-32 lens hood and I have had continual difficulty putting the hood on straight and when it stores in the inverted position over the lens it fits loosely. Due to the difficulty installing the hood for use, it frequently causes vignetting in the corners if you aren't checking the viewfinder closely and has also recently caused a large dark area in the bottom center of the photos.
Summary: Lens hoods not only protect the lens against flare, which helps make better contrast in the image, also protect the front element against rain and dust. If you own a 18-70 or 18-135, don't even think about, just get it.
Pros: Durable, Easy to Use, Improves Function, Lightweight
Summary: Using this new lens hood may help defray unwanted light, but its mount to Nikon lenses is not as secure as the "old" screw on type lens hoods. So far, I have lost one when it fell off on a fishing trip (lens hood overboard!) and another one lost when it dropped off while just walking along on vacation....It would help if Nikon would make these so they "clicked" or "locked" on better. Not a fatal flaw, but don't be surprised if you end up losing yours like I have.