I'm wondering if anyone has tried the Adventure Medical Kits Thermo-Lite Bivvy Sack? If so, which one (1-person or 2-person)?

They look interesting, but I wonder if a night's stay in one would leave me drenched in sweat/condensation? Overall, would a bivvy tent, tarp, or large tarp/poncho be a better alternative? Size is important since I'm looking for an EDC shelter. Right now I'm using a 55 gal. liner per Lundin.