Personally I'm not too worried about Ripple concentrating power in the hands of it's founders. The massive pre-mine and idealistic "Trust us to distribute them fairly!" approach is bad enough. But the crazy IOU and trust system is way too confusing for the average consumer. People don't want reputation-backed IOUs, they want cash in hand.
What difference is there between "cash in hand" and IOUs? The only difference I can see is in the degree they are trusted. After all, conventional cash is just as much fiat as any cryptocurrency IOU.
Because the risk of a gateway getting shut down or hacked is far less than the chance of your dollar dropping by 100% of it's value overnight.