+ Less stray light and thus less image degradation, because you were, always photographed from the shadows (especially in sunny exteriors helpful)
+ Lens protection against bumping
I have no comparison to other, cheaper second-party, but the original lens hood Canon provides for a plastic part made of quite high quality. Knocked out externally smooth, but "matt", matching the look of the lens (EF-S 15-85), from the inside as velvet, so that there are no reflections through the plastic.
Of course, the lens hood sits perfectly, but that can be expected from an original part also. Finally, the lens is also good to use (ie, zoom ring and manual focusing) when the lens hood is wrong when not in use around set on it.
The only downer: the built-in flash of the EOS 1000D can with attached lens hood forgotten since the lens at the image then even more shades than anyway without aperture.
Conclusion: Buy recommendation, despite the hefty price!
