I was going to reply tonight on the roller thread I started a few days ago. I've just been on it for a few minutes and I love it. Mines a really hard blue foam roller with knobbly bits!
When I first started it hurt, especially on the calf muscles when it found a lumpy bit. After a couple of weeks I can apply more pressure without pain and the feeling is quite pleasurable. It's like pain but it doesn't hurt, that sounds strange but others using a roller may know what I mean. I'm not giving mine up, it works for me!