Yes, I just got it installed.
I had the MINI tech install it, and as someone who has spent a fair amount of time crawling around cars and stringing wires, I could tell the tech was not having fun doing it. He spent about 3 hours in various contorted positions, most of the time I could not see his head above the door. I remarked to my MA how it looked like the install was a huge PITA and he agreed. Said the techs groan when they hear another Garmin unit is coming in to be installed.
It looks pretty simple, but interior panels need to be removed and running the wires is challenging. The power tap is on the passenger side, which means the wires have to span the cabin. In the UK I think the cable run is much shorter and easier.
I was going to hold off on giving the unit a review since I have a couple of issues, and wanted to make sure the unit was OK before spouting off. I have an appointment with the service dept to get to the bottom of the issues (it reboots when power is applied, and I am not receiving traffic). But since you asked...
The device itself is a Nuvi and works pretty well. The user interface is simple and easy to use. The routing is good, and the map seems accurate. The device knows the speed limits of most of the streets I drive on, and it is aware of school zones.
You can select the icon for the GPS position, and they provide a few little MINI images, but no freaking VO (dagnabbit). I use the boring blue arrow.
The device mounts in the MINI "Click And Drive" mount, which attaches to the back of the speedo. The Garmin is in a good position and securely attached it doesn't shake or wobble at all. There is a short USB cable that connects the device to the Click And Drive unit.
You can't adjust the position of the device. On the one I got, the nuvi actually sat tilted a little, which looked dorky. I ended up putting a little piece of plastic in the mount to level it. Your Mileage May Vary.
If you don't want to use the unit, it's very easy to disconnect, and the arm that it mounts to rotates to the left and hides in a slit behind the speedo. You almost can't tell that it's there.
Even if you pay for the install, it's still about $1000 cheaper than the built in unit, and from what I'm seeing on the forum, the factory unit doesn't do as much (no speed limits, traffic, and you have pay for updates-- Correct me if I'm wrong, please). This unit seems a good value, considering how nicely it is integrated with the car interior.
I like it, and recommend it.