I use the thorn resistant tubes. For a spare I carry a non thorn resistant tube, because it is lighter. Sure you can tell the difference when you hold them in your hand. But I can't tell the difference riding on them.

Do they work? I dunno. I don't keep track of miles per tube, miles between flats, tube types, etc. But I use the heavier ones just because. When I have a flat there is usually more than one item thru the tire; small staples, glass, thorn points, etc. But only one puncture in the tube.