I wanted to be able to fix my iPhone 4S to a tripod so I could take time lapse movies. This is the perfect thing.
The cardboard box it comes in is meant to make a tripod, but that's a waste of time so throw that away. When used with a tripod or gorilla-pod, this holds the iPhone perfectly steady for time lapse shots, movies etc. The standard Glif would have worked for that, but I'm glad I got the Glif plus as it's more secure with the extra piece, and that increases the number of ways you can use the mount.
One minor gripe - the mount covers the volume up/down buttons, which is a shame as one of them can be used as a camera shutter on the iPhone...
Considering the cost, it comes in basic packaging with no instructions inside. There may have been instructions on the outside of the box, but the Amazon reseller sticks an impossible-to-remove label on the box, so if the instructions are there you can't read them.
Overall I'm pleased with my purchase. It's made to suitable tolerances so it holds the iPhone correctly, and I suppose that's what you're paying for. But I would rather have paid half as much for what is basically 2 pieces of plastic. It would have got 5 stars if it was cheaper and the sticker hadn't ruined the box.