Received my I7 256GB on 8-6-14. I ran Windows Update, Scanned it with Defender, and was about to load Malware Bytes before beginning typical clean up and software loads. But first, I decided to test for the optimal screen resolution (for me). When I selected the second resolution, the screen went blank, and unit powered off, never to power on again. It was charged; no battery issues. The keyboard lights up when pressing the power button. If I plug in a flash drive, the drive lights up as if the Surface is trying to boot from it, but no video. Yes, I've tried all the troubled shooting suggested by Microsoft including the multi-button start up. I've opened an exchange with MS, and I am waiting (mostly) patiently for my replacement.
BUT, I am an official Surface Pro 3 I7 owner, even though it was only operational for about 30 minutes. Perhaps in a week or two, I'll be a happy owner of a hardier unit.
In the interim, I am enjoying the knowledge and banter in the forum. Thank you to everyone who has posted their experiences, suggestions, and even complaints about their hardware.