December 6, 2011 1:24:46 PM PST
If you look into it, there is little indication that creatine supplementation can cause kidney trouble. Admittedly, they haven't run large long-term continuous-use tests yet though.
http://www.ncbi.nlm.nih.gov/pubmed/15707376
Personally, I find creatine useful during the summer. I spend eight or more hours a day moving and assembling windows, then head to the track for a couple hours of high-rep workout (overtraining, I know). Without creatine, it's hard to string together a week at a time. I've never noticed increased muscle mass that I would attribute to creatine, or even water retention really. For me, I just notice more muscular endurance.