The base E-TR model with the addition of a personal entertainment screen. Has no one ever heard of an iPad. The bonus to using the iPad is when Apple decides to go to a 10k resolution screen, you don't have to trade in the treadmill.
This model exists because some clubs must have their treadmills with an individual screen. If you buy this for your home, take some time out of your daily, 'running into a brick wall head-first' routine and get some sense.