I have an earlier version of this accessory and lately have been using it quite a bit. I see by their graphics that they've solved one of my main issues, which was the inability to hold blades wider than 2.00".
You'll still need to polish the back side manually, or with some other device. I've been using the WE stones and DLF to do the back. I've found that I only need to polish the first 1/8" from the edge, so that goes really fast too. It takes very little time to produce a perfect, polished micro-bevel. This is not intended to remove significant amounts of steel, so if the edge has any nicks or chips, you'll have to re-do the main bevel on a grinder with a fixture, but that's true for hand sharpening too.