There is no question that the E4c will have superior noise isolation. They have accurate bass, but the HD 580 will have louder bass due to the larger drivers.
Ease of use? Well, it's definitely easier to slip the HD 580s onto your ears than to put canalphones in IMO. I prefer the foam tips to the rubber ones, and it takes a few seconds to squeeze the foam down to where it'll go in your ear canals. And then you have to adjust them to get the best fit. It's not really a big deal after a bit of practice, though.
Just about any open style headphone is more comfortable for extended listening sessions, as I've owned several sets of Shure & Etymotic canalphones and they all made my ears sore if I wore them for a long time. But the noise isolation is great and there's no question which one I'd rather have on a bus/plane/in a library/etc. In short, canalphones are great for "on the go" listening but at home I much prefer regular headphones.