I received mine: i5 256GB. Installed the necessaries. Very fast. This was an upgrade from an SP3 i3, so I'm easily impressed.
One thing concerns me: I've had the screen shake (meaning the whole desktop moves to the right briefly) and the screen blanking. It's happened a few times under very specific conditions. OneNote, for one. Also, scrolling through face book very predictably produces this. In addition, occasionally the screen will turn just the tiniest bit blue. Same conditions. That happens opening this very site, in fact. Also scrolling through facebook. I'm trying to decide whether there's a problem with the screen or some sort of bug. It's very odd. I can demonstrate if anyone's interested.
Got mine on the 26th (it's now early 27th, still playing around with it ) delivered from Microsoft Store preorder. Core i5, 256 GB SSD, 8 GB. This is an upgrade from a 256 GB Surface Pro 2. So far, I've noticed the same hue issue in Edge browser and the Intel Display Driver For Windows 8 (literally what it said) crashed while scrolling through the Facebook webpage in Edge. Otherwise, very impressed with the screen, pen, and SSD performance.