Review (4/5): Good for face.  Ok for head
I recently started shaving my head and looked at the cost of cartridge razors and replacing them weekly or every two weeks. I thought an electric would save a lot after the initial cost of the razor.
Face Shaving: Reasonably fast and a no stubble cut. I don't have a full beard so the razor is more than adequate to cut my mustache, chin, and front part of the neck. Due to the direction of hair growth you might have to make a couple of passes over the same area. I can have a smooth shave in less than 5 minutes, rubbing with or against the grain.
Head Shaving: This takes about 20 minutes with the electric alone. You have to go slow or make several passes to get everything. The time tradeoff isn't that great so I've gone back to blades for head shaving. Where the razor really comes through is touch up work after using a blade. Since hair on the scalp grows in different directions, you're never going to get it all unless you really carve up your scalp. An electric lets you work an area in a circular motion and get all the stubble. It's also really good for times when you aren't near a sink or you've got some annoying stubble you need gone right now.
I wouldn't sell the razor now that it is part of my routine and I doubt there is such thing as a perfect razor. If you want to go electric then it's a good razor. If you want to use it on your head, keep in mind that it won't be your primary razor and you'll be bringing it with you keep things smooth until you can get to a blade.
Keep in mind I'm picky (and so is my girlfriend). A good shave means you should be able to rub your fingers across the skin surface from any direction and not feel stubble. I think a combination of blade and electric will help you get close to the perfect shave.