Mclane Battery Powered Edger Trimmer
If you want the only true battery powered edger on the market, than the Mclane Battery Powered Edger Trimmer is your only alternative. The Mclane name means it is built like a tank and will last longer than your lawn will, but the price is up to 10 times some of the lower cost units on this list. But battery powered means it's extremely portable, and you won't be tethered to a cord.
Most importantly, it delivers between 90 minutes and 120 minutes of run time, and that should be enough power for virtually any city and most suburban lawns. It has an easily lowered three blade edger, and an adjustment so the blade can be tilted to virtually any angle which makes incredibly precise cuts. At nine inches in width, it will go as deep as the other selections. It rides on ball bearing wheels, and the head rotates to turn it into a trimmer, making it incredibly versatile and functional.