I think that would be useful and interesting comparing your personal experiences with fraudolent orders with the various vendor system. This would be great help for those starting to choose, and as well to evaluate a possible change for developers already using one

My ranks:
1) Plimus - excellent. Only one after LOT of sales... percentage would be 0,01%
2) eSellerate - a bit disappointing, about 7% of fraudolent orders but I guess that's the norm?
3) Regnow - didn't sold much with them, but got 20% of fraudolent orders!!!