Launching the dock six months later than the phone is not a smart move and now I've got it I can't see why we've had to wait so long. I placed my order in December but finally the Galaxy Nexus Car Dock has arrived. At the list price it feels expensive but at the prices I'm starting to see now it is in stock it feels reasonable - but only just.
Mounting: The cradle will only mount onto glass or another equally smooth surface as it uses the suction cup mechanism. Put the mount flat onto the windscreen, push a small lever down and hey presto - you're good to go. Samsung do not provide any additional hardware to allow you to mount on the dash, so if you've no room on the windscreen I advise you to look at other docks instead.
It is also worth observing that a badly placed dock, given its size, could be a dangerous obstruction if badly positioned - I find these things are best placed on the right-hand side of the windscreen at eye level - and definitely not under the rear view mirror.
The Dock: The dock itself looks huge (and it is big) but is also lightweight. The size is emphasised by the thick plastic shell the phone sits in which has a 6mm thick border all round. Volume and power controls are duplicated and the three power pins are there to charge, together with holes for the two microphones top and bottom, and cut-outs for the speaker and camera. At the base of the mount there is a USB 3 socket and stereo output so you can use Samsung's own car charging lead (provided) as well as something like the Belkin Tunecast
to send audio to your car stereo if you lack bluetooth connectivity.
In Use: Getting the phone in and out is a minor struggle. The dock holds on to the phone through friction only so insertion and removal needs gentle brute force. I suspect this will ease a little with time but at the moment I take the dock off the windscreen to take the phone out, and put the phone in before remounting on the windscreen. Once in, and on the windscreen, the phone can be used in landscape or portrait and is easily adjusted. Use the car mode application of your choice to provide those big buttons for ease of use on the go - the phone recognises that it has been inserted into the dock but only if you have the USB power lead connected.
In Summary: this is a functional, slightly overpriced and horribly late accessory for the Galaxy Nexus. A different design could have been smaller and this, combined with the price, is the reason I give four stars.
Update: After playing with the dock today I have found that you can only use it in landscape mode by rotating the dock clockwise (so the top of the phone is on the right, bottom on the left). The dock will not rotate anticlockwise more than a few degrees.