Love the fit and stretch! These don't leave undie lines under my cotton leggings, but I haven't tried them under performance material (I personally prefer thongs or nothing for working out). I've been washing them by hand as instructed, and so far no fading! These arent the *most* breathable undies in the world, but that's to be expected as they aren't cotton. These are great for daytime wear, but I'd advise wearing cotton (or commando) for bedtime! Overall,highly recommend for daytime wear!