I think this is a great idea. Unfortunately, several of the images have alignment issues and other problems. One of the mockups thumbnails covers up the user's thumbs with the screen, for example: http://smartmockups.imgix.net/47_bg.jpg?fit=crop&w=360&h=270...
Also, have you thought about doing some basic colour balancing on the uploaded images to match the environment in the image, or overlaying some subtle alpha-channel reflections? (Both of which would greatly increase the realism)
Also, have you thought about doing some basic colour balancing on the uploaded images to match the environment in the image, or overlaying some subtle alpha-channel reflections? (Both of which would greatly increase the realism)