It's hugely different. In one case, resources and energy that exist only in finite supply and could have gone to productive uses are wasted. In the other case, there is no waste at all.
I disagree completely (shocker!). Even if the sole purpose for consuming energy by mining XRP is to prevent OpenCoin from having total control over the distribution of the currency, it would be worth it in my eyes. Obviously you will have a different opinion.
But my proof of work proposal for distribution of XRP is compatible with Bitcoin merged mining so how much is really being wasted? Certainly not all the energy. Maybe some of it (very little).