Interesting enough is that, both zoom lenses have IS. I found IS pretty useful when the ambient light is weak, for examples, for all indoor settings, or when the aperture is small

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Oldfield's Inner/Outer World: Focusing speed

Open up the aperture of the lens to its maximum value (on prime lenses it can be as large as f/1.2, while on zoom lenses it is typically between f/3.5 and f/5.6), which will make the depth of field very shallow, shoot at an angle and …

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Texture Photography

A Pictures Worth: I’m a zoom lens kind of guy — mostly because zooms are versatile. But I’ve been intrigued by prime lenses for the simple reason that a good prime at a big aperture can give you really nice separation of foreground…

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Reviewing the Nikon 85mm f/1.4D AF – A Picture's Worth