The Canon EF 28-90mm f/4-5.6 II Lens is basically the same lens as the Canon EF 28-90mm II USM Lens. The exception is that it utilizes MM (Micro Motor) in lieu of Micro-USM (Ultrasonic Motor) for autofocus.
The realized difference between these two lenses is that the Micro-USM version will focus a little faster and a little more quietly. And the non-USM Canon EF 28-90mm f/4-5.6 II Lens costs less.
Otherwise, read the Canon EF 28-90mm II USM Lens Review to see what else you get (or don't get) with the Canon EF 28-90mm f/4-5.6 II Lens.
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