Contemplating trying out a bivy. Don't need anything too robust. I just run my bag and pad under a megatarp, but am thinking about picking up one of those two bivies or something similar to run when I don't feel the need to set up the tarp. Mainly needs to keep the bag dry from dew, or late season condensation from inside the tarp. Definitely won't be used alone in a rainstorm. Idea is to always pack the tarp and bivy, and if it's just a nice summer/fall evening to just use the bivy without the tarp. Anyone have experience with these two bivies versus each other? Or anything else similar?