The Sonicare UV sanitizer is a luxury that not everyone can afford. If you're a stickler for germs or bacteria being anywhere near you, then you'll probably want this to clean your Sonicare heads. It also cleans other types of brush heads, as long as they fit. I noticed my toothbrush was clean, but other than that I didn't notice anything different about brushing.
Some people are afraid of germs or bacteria, though, and a dirty toothbrush head can put them off from brushing. While sonicare brushes come with brush head protectors, this cleans them better than I would, usually. It is a self-contained unit and plugs in easily, making it unobtrusive in the bathroom. If I didn't have to pay so much for it, I would reccomend it to anyone who likes cleanliness.