"No Start button" Great thing actually. Instead of hitting start and fumbling with the mouse to find a certain app, you just start typing the app name, press Enter and done.

"Start-up screen is kind of overwhelming and inefficient". The new start screen is basically a launcher + notification. You can always turn live tiles off and get a static screen.

"Some of the features are hidden and require a lot of exploring to get it right" Win+C to show the charms bar, win+shift+. to dock/undock app to right side. No need to even move the mouse.