Depending on the type of slatted rack, it could interfere with the screened bottom board. The older style racks had the slats running perpendicular to the frames, which means that mites falling from between the frames had a 50% chance of hitting a slat and not falling to the screen. I have seen some newer designs that have the slats parallel and under the frames, this would eliminate that issue.
I use to swear by using slatted racks as it eliminated bearding for me. Once the screened bottom board was introduced, I have switched to them and it is also eliminated bearding.
Unless you are really crowding the bees, I don't see the need to use the slatted rack, the screened bottom board gives much better ventilation, especially if you provide top ventilation as well.