Steem-ua was a solid contender and at some point even open-sourced. But I think it may be too computationally intensive to be integrated in HiveMind.
Even though it still had some opportunities to be gamed, they were few. But I think the recent AV evolution may have hurt the ranking of some in that metric. Still best potential alternative I have seen to the current model so far.
Yeah it was, although I am not sure about what they were actually calculating still. Too much weighting on being a witness also. But if I remember correctly, they were calculating billions of points.