Have used a couple but didn't find them that effective as promoted but didn't lose out on them more a less got back what i invested.
I found @minnowbooster to be the better one @randowhale sleeps to much...lol
But really i would like people to rate you not machines that's why i don't use them anymore :)
You are the first to bring up promoting! I have never used this feature personally and would love to join know more about how it works.
Incorporating the final payout you feel you broke even, does that include new followers & steem rewards or the amount of sbd?
What about Steemit communities?! Do you find them helpful?