In the past month I have been experimenting with bots as well. In the beginning I was loosing on my investment. One of the reasons was the Steem price dropped. You just have to figure out when it’s the best time to use them. Eventually I have used @tipu as well. His ROI is one of the best and I will continue using him. @smartmarket is great as well since he upvote you right after you send SBDs to him, which means before 28 min your post was published. This give you most of the curation rewards as well. Keep experimenting and letting us know.