Backpacking Discussions

Which is better for water purification, Iodine or Chlorine-Dioxide treatment?

I have both iodine tablets and chlorine tablets, and I'm not sure which ones work best. I've tried them out and it seems like the iodine leaves a bad taste in the water, while chlorine not so much. Is there a kind that is better? It was a while back when I bought them so I'm not sure what the price difference was.