I have been looking into being better prepared to spend an unanticipated night somewhere. Weight is a big factor. In researching I cannot determine if these $15, super light weight "space blanket' based things are even worth getting. Maybe i would be better off just packing an extra waterproof, light weight poncho? I see a variety of prices and varieties for emergency bivies, but just can't find solid info on what is worth bringing along. I feel like some are akin to those cheap, prepackaged first aid kits that only have some small band-aids and a few pieces of cotton. Then again, I only want it for EMERGENCY situations to prevent hypothermia.
I would love to hear your input on this.