Sooo I guess you can say I am finally a happy camper. Sadly it has taken me 4 units over a period of 3 months to achieve this. With that said I think Microsoft may have finally nailed it *crosses fingers* Each one of my previous units had something wrong with it that was unique from the others, however all of them had two things in common. (light bleed and intermittent screen flickering) The light bleeding issues I assumed were unavoidable and learned to roll with it and the moderate screen flickering I rolled with it assuming it would be rectified in a future firmware/display driver update. So neither of these two common issues had a direct influence on my decision to return the machines. 1st Unit: LOT #: 1552 Casting imperfections in the magnesium housing, recessed left speaker grill, intermittent popping noises both through the speakers and headphone jack earphones regardless of volume level. BSOD's a lot, Touchpad/keyboard failed to register input quiet often. 2nd Unit: LOT # 1602 Fulcrum hinge was binding producing a clicking sound upon opening and closing. The unit had very minimal light bleed however it suffered from excessive and consistent screen flickering regardless of the application or GPU that was in use. One afternoon it literally had a seizure while in tablet mode which was the icing on the cake for me. Also this I'm sure isn't hardware specific but this machine and the previous 1552 for some od reason gave me no option to sleep. Because of this I was convinced up until this point these machines simply couldn't sleep. 3rd Unit LOT # 1501 This unit was from yesterday around noon day. This one had the usual light bleed but also a yellowish hue to the keyboard lighting; however the real deal breaker was the battery life. It took 1 hour to charge the last 4% of the keyboard base's battery and immediately after unplugging it dropped to 97% than about 1% every 2 minutes. I literally made a U-turn to my local Microsoft store and told them this had to be some sort of sick joke. I've never in my life had so many consecutive POS. (excuse my language) They told me it was brand new and that they do not give out refurbs however this was far from the truth. Upon opening the box I noticed the original box seal was cut and a newer one with brown ish residue was covering it. The inner wrapping around the unit was folded back and crumpled and the box had some lint in it as if the thing was boxed up in a cotton factory. However I was content in keeping the unit seeing that it had no cosmetic blemishes until I discovered the battery flaw. Which wasn't until after spending 5hours downloading/installing 50Gigs of content. I told them I just wanted my money back. I didn't want to have to deal with this anymore as I am moving back to Bermuda permanently on the 24th. They insisted on me giving it another shot with a brand new sealed unit they'd just received. 4th Unit LOT # 1607 Upon first start up I noticed there was absolutely no backlight bleed! Couldn't believe it. No hump either on the tablet portion.. Something I noticed on the 1602 and 1501 unit but disregarded as petty. No screen flickering at all, No BSODs nothing. Here is the interesting part. I'm not sure if there was a firmware update applied already at the factory but WSUS didn't update any drivers. It only updated the build of windows and some other irrelevant things (screenshot). I noticed the fan in the clipboard portion also behaves completely different from all the others I've owned. It doesn't gradually ramp up or down based on load/cpu temp plots. It is literally either on or off at full blast like a light switch. Because of the aggressive cooling the fan is literally on at most for 2-3 seconds than it shuts off. I'm not sure if that's good or bad but I figure Id be totally transparent and mention it. I also noticed upon detaching that you can barely hear that audible clicking sound of the muscle wire actuating, neither does the screen do that little tilt thing backwards upon the mechanism detaching. It stays rock solid where it is as if it wasn't detached to begin with. Also Windows Hello has yet to fail to startup the camera both after a shutdown or restart event. I doubt this'll be of any help to the people who are past their return period but, for all of you who can still return your Surface Book; I can say with confidence, Lot # 1607 is something to lookout for. It feels like the machine it should've been from Day 1. The one advertised to give Apple's Retina MacBook Pro a run for its money.