A good, old-fashioned shave can elevate men's grooming to a whole other level. But you can get very good results at home with the right electric shaver.       Consumer Reports tested a variety of electric shavers, 13 in all.  Two cost as little as 10 dollars  - and one was as much as 240 dollars.    "The 10-dollar shavers we tested didn't do so well. Our testers said they wouldn't buy either one."   Tests included both foil and rotary shavers. Gayle Williams, "Foil shavers have blades that oscillate behind a perforated screen, while rotary shavers have circular heads, with cutters that spin behind a fine grid." Testers shaved with either the foil or the rotary shavers for at least a week. Then Consumer Reports sensory panelists compared the feel of the post-shave mugs to various grades of sandpaper to size up the closeness of the shave. Testers also assessed battery life, and how easy it is to clean the shaver.   When all the stubble was washed away, the top-rated foil shaver was the Braun Series 7 Shaver System 760 for 240 dollars.  It has the longest battery life and gives a very close shave.  And while you can wash it under running water, it comes with a cleaning station - which can be a plus. But it can take up valuable counter space.   More of a rotary guy?  Try the Philips Norelco SensoTouch 3-D 1250-X for 200 dollars.   It has very good battery life, can be cleaned by rinsing under running water, and it ranked highest among rotary shavers."