What's the difference between a PU coated tarp and a silnylon one?
Top of the list is weight. Search for reviews on particular brands. Some manufacturers do not report accurate weights. If you get into ultralight hiking, it can make you crazy.
PU coated tarps typically cost a lot less than silnylon.
Silnylon is more flammable. All will get holes from fire sparks. I wouldn't use a stove or fire near either type.
Silnylon tarps are usually made of thinner cloth, and so are more fragile.
Silnylon is not as waterproof-- some experience misting in hard driving rain.
PU coatings can delaminate over time, but I chalk most of that to misuse. It needs to be dried well and never put in a dryer.
Tarp construction varies. For traditional tarp shelters, a flat tarp is desirable. Many modern silnylon tarp shelters are shaped tarps, most commonly a caternary cut, which has a curved ridgeline when pitched taut, which is much more stable in the wind. If you want to do alternate pitches like pyramids and lean to's, you want a flat tarp. If you want an a-frame type pitch (most room), then a caternary cut tarp is the way to go.
If you want a solo tarp for emergency use, consider a poncho. You get emergency rain gear and shelter for the same weight and cost.
Tarps are a lot of fun, very adaptable and great for shelters. I think everyone who plays in the woods should have a tarp and know how to use it. You can get a lot out of a cheapie poly tarp, it just weighs more.
As to Ben's Backwoods, I have had several dealings with him and he gets my two thumbs up.
