I had some good gains with creatine. I think it is a good supplement especially for beginners if you drink a LOT of water, you cycle it correctly, and don't allow your body to get used to it. As some people said, it is more useful to build some strength rather than to create mass (this comes as an indirect effect).
However, in the last two years I stopped using it. Now I get the same cell volumization results without that disturbing water retention by using glutamine and L-Arginine.