First of all, this works out of the box with Ubuntu 10.04 Lucid Lynx.
After inserting the batteries, via the little hatch on the keyboard's underside, I plugged the usb dongle into my netbook (Asus EeePC 1005HA) and started typing straight away. All keys were mapped correctly except the Fn+Function keys. I rarely use the Fn+Function keys, so this will not be an issue.
The unit itself is lightweight and feels somewhat plasticky, and the touchpad feels a little odd compared with my netbook's touchpad but that's easily forgiven at this price point.
It also came with four AAA Energizer batteries in the box, which was helpful as I'd (typically) forgotten to buy some.
I bought this so I can have large screen browsing and films via my netbook plugged into the TV on the other side of the room. And that's exactly what I got.