if you have to take five minutes getting used to a new start menu.
At one point I worked PR for HP, operating a new stall for them where they were trying to sell brand new Windows 8 machines. The only machines that sold were the ones that had Windows 7 or didn't have Windows at all.
The Start Screen is rubbish from a practical point of view. The Start Menu is a small, easy to navigate list that contains helpful shortcuts, but it doesn't distract you from the desktop environment. The Start Screen takes up the entire view, and only lists apps that Windows recognises as "Installed". That means that if anybody, such as me, needs to access programs frequently which are not connected to the registry, you ultimately are going to be wasting more time in the Start Screen.
Furthermore, the Start Menu is, as I said, List-Based. It keeps size down and maximises the text, which makes it easy to navigate. The Start Screen is based on icon-view. if you have programs with multiple shortcuts, the screen soon fills up and makes it hard to find what you want.
I fail to see how the Start Screen is good, even for mobile users. I played with a friends Surface 3, and both us had no issues with Classic Start there. Unless you have fat fingers, I fail to see how larger buttons serve any useful purpose.