in my opinion creatine is great and i have used it on and off. it assists muscles in producing adenosine triphosphate (ATP), the substance that fuels bursts of energy. when you start using it, it really does put help put on some mass and strength if your diet and training is good. the first week i used it i put on around 4 pounds, but afterwards it gets less effective. one thing you also have to remember is that it increases water retention so some of the weight gained is water, and not long lasting muscle which also makes the muscles feel softer, but i didnt notice this much. its also best to take creatine once you already have some muscle and a base, not immediately when starting weight training.
creatine does have side effects, i experienced some small things but alot worse can happen from taking it.