Today one of the big downsides to e-paper displays is that most of them can't show video. The screens are also generally only in gray scale as well. That gray scale bit is changing with some of the color screens that are coming to the market eventually from E-ink. The colors the E-ink screen shows aren’t nearly as nice looking as a normal LCD though. The upside to e-paper and E-ink screens is that the things sip power making the devices they are integrated into much easier on batteries than devices with an LCD. Eventually we will end up with color e-paper screens that will run full motion 30-fps video, but that tech is not here yet.