It's different to the stock item in that it holds the device in portrait rather than landscape (using the microUSB port rather than pogo pins), it has a simple charging connector rather than audio out too and it has a removable insert to support the device if it is in a case - which could be invaluable depending on your usage scenario.
I wanted the dock for my other half's bedside table, so the portrait position actually works better and the lack of audio out is a non-issue.
The dock is very well made with a great fit - the tablet docks with a satisfying click and is held nice and steady. She has a third party case and sure enough, with the insert removed it fits in great.
If you are looking for a Nexus 7 dock, i'd recommend giving it some consideration. It's currently priced at £19.95 + £2.95 delivery from GearZap.