I haven't used this poncho yet but I have tried it on. It's a nicer, brighter colour than most. It has two plastic press studs down each side to create "sleeves". It should be 100% waterproof fabric as it's plastic, but of course that means it might be a bit humid if warn for a long time.
I bought mine particularly for an outdoor theatre visit. It packs into a small bag, which is supplied, but it's surprisingly heavy for its size if you're travelling light; however, that means it's not too flimsy and shouldn't split easily. It's probably big enough to go over my backpack too, while walking. Good value.