The Blood songs are at 10-1 at the moment. I don't think one of these songs is much better than the other.
Instead I think that the people who voted for Blood Brothers are (extra) infected by Maiden's recent live performance and/or have a liking for this sweeter, softer, more melancholic sounding side of Maiden, a less complex song played in a constant tempo. A matter of taste.
My taste leads me towards a different direction. Without a second of doubt I choose for more variation and more excitement: Blood on the World's Hands. Reason: This is an awesome and intense performance, from beginning till end. These intelligent (and heavy at the same time!) riffs are unprecedented. So many strong elements are going on. We have the intriguing Arabic flavor in the melodies, the striking solos and last but not least: Blaze is so much into this, you really feel that he's very driven during this delivery.