Yes, I have some experience with it. I used it with a 7" el-cheapo Android tablet. It connects to the tablet by USB, which is a bonus as I have never ever managed to get any Bluetooth device work with anything. Ever.

The disadvantage is that the USB cable sticks out of the side of the tablet and out of the fake leather case, so if you want to shut the case and put it in a bag, you better pull the USB cable out.

Being cheap, there are some quite predictable build issues. It is surprisingly thick. Folded with the tablet inside, it tripples the thickness of the tablet. It has a kick stand which is nice but it is quite stiff out of the box and may need a few weeks to soften up.

The case holds the tablet by three clips: two at the bottom, one at the top. Depending on the tablet model, these may or may not get in the way of buttons, ports etc. The clips do not hold very well, the tablet slides out quite easily, but I do not think it's something that a rubber band or two could not fix. I know it craps the style but, at that price, what style?

Function-wise, I have not found any issues. As Kangal says, no drivers but generic enough to just work out of the box. My tablet ran Android 2.2 and it worked fine.

I cannot vouch for longevity as I stopped using that tablet very soon; in fact it was the accidental purchase of my first N900 that obsoleted both the tablet and the keyboard. So I used it only for a few days. But I still have it in a drawer somewhere so I can dig it up for you and find out what it looks like after all those years.

I would say, probably not really suitable for turning your tablet into a laptop and carrying around like that permanently, but good enough for plugging in from time to time and briefly bashing something on the keybard. And for the price of less than two beers, who really cares?