It doesn't leak at night as pads do, it's cheap and environmentally friendly, but mainly that it doesn't dry out my mucus membranes and doesn't contain bleach and pesticides that I don't want anywhere near my uterus.
Hip hip hooray! May they improve all menstrual weeks for hundreds of years!
You don't have to think about it, it's wonderful to go a whole day without caring about your period! Thank God for not having to use tampons!