Good signs to look for in a bidbot

It employs automatic refunds and already refunded an authentic user which is not its owner in disguise or one of his accomplices.
It has an automatic prevention against overbidding in a round
2*. less than automatic refunds in case of overbidding, but still better than nothing, is when it automatically refunds bids over a certain size
Its owner, his family and accomplices do not interfere in the bidding rounds. No self votes either.
Its owner/operator is responsive in steemit and does not hide behind steemit.chat / discord / other platforms accounts
The bot account vests Steem instead of only renting it.
It votes on comments
It employs a blacklist against spammers
The higher its total vote value/minimal bid ratio the better.
It shares its revenue with its frontrunners in case it has any. Frontrunners should be considered as steem delegators or vote sellers.

Personally I prefer bots which are not "grumpy compliant", and allow late votes freely, due to comfort, but a grumpycat vote can destroy most users' reputations, and also hurt their post's reward and ROI.

It votes in the same chronological order of the bids.

I know a good vote bidding service which does not obey this rule, and it causes some injustice both for earlier bidders and for frontrunners.
It is a property that I would rather have, even if not one of the most necessary, it is still necessary nonetheless.

It automatically claims its rewards less than 6 minutes before it starts its voting cycle, possibly during it as well if they exceed a certain amount relative to its size and not every time they occur, in order to ensure growth while not abusing the blockchain.
No bidbot that I know about does it this way.

2018-3-18 update, due to inability to edit post after 7 days from its submission.

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