I have a Tanita, which is considered to be a high quality brand for bodyfat monitors. Mine measures weight, % fat, kg lean, % water, kg bone, gives an estimated kcal/day, gives a sort of rating for your physique, and gives you a metabolic age. Oh, it also gives a rating for visceral fat too. I'm most interested in getting that metabolic age down, and keeping it down!
Different people may be motivated by different data. With these bodyfat monitors, can be important to step on it under the same sort of conditions/time of day. If you step on first thing in the morning, your body is more likely to be slightly dehydrated, so your reading will show that you weigh less but have a higher bodyfat %. Whereas if you step on later in the day, your body is probably better hydrated, so you will likely weigh more and have a lower bodyfat %. Therefore it's more important to look at the trends over time and how they change, than to look at the absolute values you see each time you step on.
The machine sends an electrical pulse up one foot and measures how fast it travels thru your body and reaches the other foot. You can't feel it. If you have lots of fat, that impulse is slower. And if your body has lots of water, it goes faster. People with heart pacemakers and other such devices shouldn't step on these scales.