I shave my head. There... I said it. For the past seven years I've been shaving my head completely on a weekly basis. During that time I've tried several different methods and setteld on the Gillette Mach 3 Turbo as my razof of choice.
The cartridge contains three separate blades to give a very close shave; much closer than I was ever able to achieve using an electric razor. The blades glide smoothly across my scalp when they're new, but I've had more than one (bloody) incident when I tried to use the blades after they started to become dull.
Shaving on a weekly basis means that this razor must cut through regular stubble, as well as longer hair, and it does so very well.
I've seen commercials for newer, supposedly superior razors, but at this moment I don't feel any need to change.