I've come to the conclusion that upvote bots are a waste of time and money (at least for me). Tried power down then setting up bids only to end up at the same position in Steem I was a month ago. The mathematics behind these bots seem to lead toward a recentralization of wealth rather than a distribution of wealth as I had originally thought.
Maybe it's different for those with a rep score below 60 or so, but I think if you have a rep above that and still have to use bid bots, then your work must be trash or the platform is broken.