never tried it- don't know anyone who has- some bros i know theorise that it could be used for better effect during a cycle. but everyone i know usually saves it for post cycle.
Creatine is good post cycle because it dosent interfere with recovery, and can stop weight loss (or some of it).
The only thing whilst on cycle to watch out for is muscle tears. I use it whilst on, but my TP always tears a muscle, usually chest, if he goes near the stuff. Probably because when your on you train a little harder etc. and the creatine just dehydrates enough to make the difference