The solid shade is going to focus the light downward. Tape a sheet of stiff paper to make a cone around the bottom edge to see where most of the light will be [inside the cone].

The mesh shade appears to be about 60% solid, so that means about 40% will distribute the light outwards instead of downwards. You won't have much of a "spotlight" effect on the counter, but you will have to be careful to keep the light well above eye level.

If you want widespread lighting [across the room], the mesh is better. If you want a specific area lit, the solid is better. If the lights are placed comparatively close together and very high (in ceiling), the solid "cones" of light will overlap on their way to countertop and give a more uniform feel of brightness instead having a spotlighted feel.

Keep in mind that the solid cover is going to somewhat hide the track in shadow, while the mesh cover is going to make the track very, very visible.

And one more, negligible thing... those holes in the mesh cover are going to be dust collectors.

The mesh will vent heat better, too. If you use conventional bulbs, they may last longer. Over time, the vented shades may also cause the immediate area around them on the ceiling to become somewhat dirtier than the rest, due to a constant flow of heated air up and through the shades.

Thanks for the knowledgable replies. I think we've got it.