I'm very happy with @emperorofnaps
I've been testing various uvbots recently and tracking the results by refreshing frequently to see the impact of each bot. Sometimes I miss them and will have two or more votes since refreshing, and therefore can't accurately tell the exact impact of one vote.
But on my first recorded test, my half-Steem (worth $1.35usd that moment, so $0.67) resulted in an upvote from eon worth $0.95usd. My second result was 1 full Steem ($1.35usd) returned me $1.87 usd upvote - 138% return in minutes (plus waiting a week for the payout of course).
Results will vary, but eon is a great upvote bot to use, imho.