What do you think of Foam Rollers for sore muscles?

I ESPECIALLY would like to know from people who use them. I'm thinking about buying one myself. Stretching after my workouts usually does the trick, EXCEPT on my Quads. To a lesser extent, my calves too. I was thinking of maybe buying a foam roller, because my Quads usually stay sore for about 5/6 days.

Rollga Foam Roller