I regularly shave my head with an electric razor. I only use the Gillette Mach 3 and shaving cream when I have the time and patience. And occasionally I use a double-edged blade when I want to do the full shaving ritual (but I usually cut myself on some spots).
For the last three months, I've been using the new Philips headshaver 9000, and the results are very good. Before, I used a Philips Series 7000 designed for the face, and although the results were also good, the ergonomics made it very uncomfortable. My arm had to be in a somewhat awkward position. Now, with this new headshaver, which is specifically designed for the head, the results are even better, faster, and the ergonomics are perfect for me. It doesn't shave as closely as a razor, but the results are almost perfect.
One thing to keep in mind is that the three Philips Headshaver models (at least in Europe) are identical. The difference between the 5000, 7000, and 9000 models is the included accessories.
I continue to use the Phillips Series 7000 for my face, as I've decided that a mustache is the most practical and attractive look I can sport, and for that task, it's a perfect shaver.
Oh, I also have an Andis Profoil, but I hardly ever use it because it can't get wet and it's very noisy, although the results are excellent.