I've been hand filing for 30 years and still can't quite get away from ending up with teeth a bit shorter on one side after 3 or 4 full sharpenings. Have heard different explanations for it, but I guess it comes down to simple differences in how we approach the teeth with the file from one side to the other. Nevertheless, hand sharpening has always worked better as far as being more in tune with how much metal you're taking off, getting the proper shape and angle, and manipulating the process in general. Lately, I've been doing the "Get the gullet" method with a nice C and the results are fantastic. It's a learning process to go the hand filing route, but I wouldn't sharpen any other way. You'll never get perfection with the hand file, but you don't need it. If your rakers are kept where they should be, and you keep your angle approximately correct, getting a good cut isn't that difficult. I'm happy when I'm throwing chips.