Steemit voting bots are clear scam, don't use them. I was aware of that for a long time but I wanted to test it myself. Results are here: Spent: 20.50 SBD Received after 7 days: 13.56 SBD, 4.04 SP
In the last time too don't lucky with bots. My result: Spent: 37.50 SBD Received after 7 days: 18.75, 6.27 SP Need trying something other for promote.
I wrote this post about bots just this morning - I hope this helps
Waves lets you "lease" your coins , earning you free airdrops of other coins on there like mercury and ripto bux, crap coins...but you retain full control of your coin and can cancel anytime...waves is a good one to hold long term anyway.