I use one every day as part of my warm up for workouts. I also use it a couple times a week in the evenings more extensively to help with keeping the "knots" out of the muscles.
For me since I've been using it I feel I have less muscle soreness and my body feels much more prepared to work out when used in the warm up. I would definitely pick one up and think it's a great tool for anyone to use. There are a lot on how to videos on youtube that will help with technique for the majority of muscles and groups.