If you want to make yourself feel better, go with the scale that shows you weigh the least. However, I would not trust a scale that I have to constantly rezero.
On a body fat type scale, if your feet are damp, you will usually get a better (read lower) reading because there is less electrical resistance.
If you really want to play scale games, be sure to weigh yourself on the scale that reads the least. Do it in the morning before you eat anything. Check your body fat late in the day, when you are the most hydrated, and make sure your feet are damp.

Actually, you should measure your body, and go by inches lost. This is what people notice when they look at you.