I've been really happy with that plastic tarp for all of my tests, and I think it cost me all of about $4 for the plastic and a hair more for the cord (dropline). There are a couple nuances with it that you've got to watch for. You have to be really careful not to snag and puncture it on anything. There's a few small holes along a couple edges of it where it was blowing around in the wind and snagged on the top of my chain-link fence when I had it set up in the backyard. Also, it stretches somewhat, but if you put too much tension on it, you'll break it. I've torn all four corners off, because I was trying to use up as little of it as I could when I attached my tie-outs, but there just wasn't enough meat to hold with the amount of stress I put on it. I just gathered up the remaining material (thicker this time, since the thin corner was gone) and re-tied it. Next time, I think I'll cut it slightly larger to account for the material lost when gathering up corners. Also, I think I'll try a six point shape instead of a four point shape, kinda like a tadpole tarp. I haven't had it out in a storm yet, but I worry the coverage might not be sufficient for wind blown rain.
One other thing that doesn't really have to do with performance, is it would be nice if it was clear instead of hazy. When I was laying in my hammock the second night out, I was thinking how nice it would be to see out, especially the stars. The moon wasn't up yet, and the stars were incredible. I may replace the tarp with window film at some point ("polycryo"), because it's completely see through and is supposedly a little tougher too. Of course, if it was clear, it might not hold heat as well.
That reminds me. Re-reading through my report, there were several things I remembered that could have gone into it.
1) Using my water filter was really tedious. I may have to figure out a poor man's gravity feed system I could hang up in camp and during lunch.
2) The stars were incredible out away from town!
3) I slept balled up in my hammock the second night, in order to stay warm, but I woke up with a very stiff left knee.
4) The coyotes were out. Their calls are such a haunting sound. If I didn't know Stephen was 30 feet away, I might have been pretty creeped out.