I met with a friend who is an IT manager for s software company here in Atlanta for lunch yesterday. He has now rolled out over 40 Surface devices for various in house and on-the-road staff. He brought his new i7 dGPU Surface Book for me to check out. He now has a few of just about aver model of Surface with the SP4 being a close second in total quantity but he also has S3, Sp2 and SP3 units. Of the 40 he has purchased he tells me he has only had problems with 3 that got replaced. One, a SP3, had a fan that sounded like breaking soda crackers. One had a charging port that failed and one had a bad USB port. (He thinks the USB problem may have been created by the user). Despite having 3 replacements he tells me his experience with Surface is as good if not better than any other portables/laptops the company has used. That failure rate really isn't all that bad. he says nobody has had any complaints except for a few people who left Outlook open when they closed the cover and lost substantial battery until they realized what was going on.