Quality "Made by canon", fits without pb (remember to pass the cable into the slot provided for this purpose), slide in the unit (working in my Mark II and Mark III) for shooting without battery constraints (video, studio, ...). I plan to use it in stop motion macro, you do not want to have to touch your camera because the battery is empty ...
Between the transformer's power cable and that which goes to the "stack" So you have about 4m plenty to position itself without extension.