The suit's a great midweight base layer (very similar, if slightly thicker, than Burtion midweights for reference) and the material is everything you would want in a midweight base layer, warm, wicking, etc. The fit for this year's is kind of strange, though, with a pretty long torso. The rainbow flap is a good idea in theory, but in actuality, the zipper just chafes your ass and tends to rip pretty easily. I had mine modified to take the zipper out, quite frankly even if you have to take a dump you're not going to use the flap. Still, this is pretty much my first layer of choice for any day in the EK.