I own a spinnaker tent (Gossamer Gear Squall Classic) and a spinnaker tarp (GG Spinntwin) (both the special fabric made for tents). I haven't tested the tarp yet (waiting until bug season is over), but I've used the tent for several years in all sorts of weather--it works fine. The hype that says it doesn't stretch like silnylon is a bit inaccurate; it does stretch when wet but not as much as silnylon. Thanks to linelocks, though, I don't have to go out in the rain to tighten anything up. I've had no issues with misting, even in heavy rains or with a garden hose (with pressure nozzle) turned on it for almost an hour. To repeat, however, this is not the kind of spinnaker used in sails, and it is getting very hard to find.

I've used silnylon tents under similar circumstances (nasty weather and the garden hose under pressure) and have never had any misting. The tents were by Tarptent and Six Moon Designs. A lot depends on the quality of the silicone impregnation, as I understand it.

Quite a bit of spinnaker's crackly noise goes away after some use, and if the tent is pitched taut, the spinnaker is no noisier in wind than any other fabric.

The determination of the waterproofness of a fabric is normally done with a gizmo that puts it under measurable pressure. (As a non-engineer, that's about all I understand about it, sorry!)

I do have a few pieces in cuben fiber (a couple of dry bags), and like them--but there's no way I can afford a $500 tent in the stuff! My other concern with cuben is privacy-it's pretty transparent, so you can't depend on the tent to block the view when you're changing clothes! I did get a chance to look at a cuben tent earlier this year, and if I ever win the lottery....