i have tried a few hammocks. Don't use the net models, thing will catch on the net, which is annoying and a great way to loose or damage things.

I also dislike the models which are made of a large piece of fabric, but ends on both ends with strings and a big knot. The strings get tangled up, creating a mess.

Not sure which brand or model i have right now, but it's made of a single piece of nylon fabric, with mosquito netting. The smooth fabric prevents things from catching and there are no strings to mess up. Just the rigging lines.

Never tried a double layered hammock. But i have always find it a challenge to get mine sleepingpad just right...