I also bought my first scale in years recently. I got a Tanita and it cost quite a bit, and yes, it does measure body fat percentage and total water percentage. These numbers are of interest to me, especially the body fat percentage.
When I weigh in the morning, my weight is down, my body fat % is up, and my total water is down. When I weigh in the afternoon, my weight is up, my body fat % is down, and my total water is up. That's how I figured out that indeed, I can have a 3-pound difference just from water weight.
As long as a scale is reasonably accurate, it doesn't matter which kind you get. Just always use that scale, and record your weight at the same time of day wearing about the same clothes (or none). That way you'll have consistent readings.
Jay