I did a cycle of cel-tech a few months ago, mostly out of curiosity since there's so much conflicting information and controversy about creatine. I didn't notice any crazy weight gain, or huge muscle mass increase. What was very noticeable was a strength increase and especially muscle endurance after about 2 weeks. Most of my lifts went up by 15-20% in weight, but stuff like surfing and hiking got more difficult since it's easy to get dehydrated quickly and develop headaches. Drinking a gallon of water every day isn't as easy as it sounds, especially if you're actively moving around outdoors.