Used to use paste wax, predominantly use silicone spray now.
When you're using the machines pretty much all day every day you don't so much need a protective film so much as you need just a little slick now and again, Used wax for years (Big 5L Fiddes tin) but I was finding that having to turn off the machine, letting it spin down, lower tables / remove guards and apply new wax every 30 minutes or so was getting annoying. So I started using the silicone spray and it's really streamlined everything as you just give it a small spritz whilst the machine is running without adjusting a thing and it runs through like butter, if not better than the wax in my opinion.
You do get the occasional comment about it being a totally idiotic idea because it affects the finish but after a few hundred doors, windows, staircases, kitchens etc and seeing no discernable effect, I don't think it makes any difference to the finish. Of course, everything gets sanded once it's been through the machines so any residue is sanded off if there is any.
But as far as actual moisture protection goes the wax is a dead ringer over the silicone spray, I don't think the silicone spray protects much at all from moisture but a coat of wax definitely does. Although I've never used it myself I've heard many good things about Boeshield T-9 from people whose opinion I would trust, gives a very good protection against moisture and rust apparently.