I pretty much live on my iPad 2, and have since I got my original one (which I managed to break a month ago). When I got my replacement (as I thankfully had three days left on my warranty), I decided to get a back case for the unit to protect it. Of course, I got a black back cover, and it no longer looked as awesome to have a gray smart cover... so I started to look at my options.
Sadly, the only black Smart Cover Apple makes is leather... and I didn't feel like spending $70 to replace my gray smart cover (which wasn't exactly broken). I went to look on Amazon to see if I could find a used one for sale, when I ran across this.
It was a knock-off Smart Cover. Sort of. It wasn't pretending to be made by Apple or anything, but still. At the time it was $10 (it's not in stock as I write this), and I thought "what the hell" and ordered it. A few weeks later (as I went for the free shipping option) it was in my mailbox.
And right now it's on my iPad.
And it's not bad, actually. It works fine with the iPad 2 (although Third Generation iPad owners may have problems with the on/off issue), and looks pretty good. Comparing it to the real smart covers (which start at $40), it shows it's cheapness. The cover is a much cheaper plastic than the nice polyurethane of the official ones. The underside isn't exactly a "microfiber" like the real one, but instead some sort of felt. While the spine magnets seem pretty solid, the activating ones are significantly weaker than the official one (which means it comes open more easily). But hey, it was only ten bucks.
The hinge is a little tight, so I hope that loosens up over time, but overall it's not terrible. Would I recommend it over the real one? Well... probably not. But it will do in a pinch.