I'm sorry to hear your experience with other bots. But I'm the same way though; I stick to the ones I know are legit and hold up their end of the bargain.
And as far as handling spam, I really feel obligated to do what I can to prevent my upvote service from promoting garbage. Especially considering that my bot funds @minnowfund which helps minnows get a start here. We have to set an example somewhere.
As always, thanks for your feedback and support. Let's continue making Steemit the best place to be!!