I received this car dock yesterday. The suction cup works really well, compared to the OG droid mount from Motorolla. The problem with the Samsung is the limited postioning of the phone. If you mount it on a horizontal part of the dash, you cannot position the phone 90 degrees from Horizontal. The front of the phone actually faces upward at about a 30-40 degree angle at best, after adjusting it. The ball joint has very limited range.
The unit will probably work better attached to the windshield, than to the dash, but if your windshield is out of reach, except in the area you need to see ahead while driving you are SOL. The reason I bought it was because of the hole where the rear camera can peer through, so I can use the dash cam app, Daily Roads. As it is, it is looking more at my forward dash than it is at the road ahead. It does secure the Nexus very well though. It is similar to the thin rubber case I picked up from VZW when I got the phone. It has a proprietary connection from the mounting arm to the phone holder, so modifying another mount is a problem.