Creatine is worth it in my opnion. As far as the stomach problems, I ocassionally get this if I take it with too cold of water after working out right after working out. Other than that I hve no problems. Do a search, BigKiwi had some info about anoter type of creatine or something similar that he found good results from.
I like creatine off cycle-its part of my gainskeepers program. Go on 2wks before cycle ends, and stay on until 2-3wks into cycle.
NEver bothered my stomach, and I have reflux problem due t a hiatal hernia.