A sanding screen is comprised of small holes:
A sheet of sandpaper has a flexible paper backing:
Despite using different methods of abrasion, the abrasiveness of both products is measured in grit.
What are the functional differences between these two abrasives?
Can they be used interchangeably? Should they?
Gypsum drywall and it's paper covering, spackle and joint compound are much softer than wood (except perhaps balsa) and produce a lot of dust that clumps together and sticks to sandpaper, rather than falling off as wood shavings do. The "holey" sanding sheets allow dust to fall through and therefore last longer on drywall.
However, they can be used interchangeably, if of the same grade, to achieve similar results, with the caveat that it might take more sanding sheets and more time if they're used at cross-purposes. For small jobs that may not matter.
Drywall screen doesn't load up as quick, and will tend to remove more material, than the same relative grit of paper backed. It is also much easier to create scratches, while you sand; so some people will use screen on the first couple of coats, then paper for the finish sanding.
Drywall screen tends to be more expensive as well, but you can use both sides. It's also ideal for pole sanding, when you don't have a lot of leverage, in hard to reach areas.
Aside from generic less clogging, there's highly specific drywall tool less clogging (and less dust getting free) with a vacuum sanding head, which can pull the dust right through the screen.
I use screens on wood with some regularity - they work better than normal sandpaper for some things, as far as I can tell - either hold up longer or clog less, or sand a bit faster.
