The ones I found on Amazon didn't look like the ones on the GnGo website, so I got from their site directly. I don't use it often, but just recently I used it on a 600 mile trip and it worked flawlessly. Never dropped the phone, didn't slide, just stayed exactly where I put it. The new slanted windshield on the rental car made it difficult to mount, but when I finally got it, it was fine. Lucky for me I have long arms. I can easily recommend this, and have encouraged my sister to get one for herself (if she doesn't get one for her birthday gift first).
<edit: I forgot to mention - I do use one on a mirror in the house and it's been stuck on there for about 4 months now. I had to leave part of the sticky pad insulator on the pad otherwise it was too sticky and made it difficult to remove my Nexus 4 phone.>