Personally, Im not a big fan of the gloss on the MB White, but it does hide scratches from normal use real well. I love the brushed black look, and if you wanted to make it glossy, just buy the Invisible Shield film to put over it and voila.
Also, on the black model, natural oils from your fingers, sweat and grime from your sweat/normal use will be A LOT more noticeable, and a lot harder to clean off. Scratches on the case from normal use will also be a lot more noticeable.
On black model, the gradual use of the of Trackpad will cause it to get really oily, really quick. You'll have a big spot of "gloss" on the trackpad, and its just weird. This happens on any trackpad, but much more noticeable on the black.