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
I guess that depend on the bot(s) you use...
Take a look at
https://steembottracker.com/I usually make a mix number of bots (do not put the whole value on the same bot)
You need to take in consideration that other people may use the bot and the final value is not fixed.
I have been using this site as a guide for quite a while with profit.
Usually I spend 5 SBD, and in return I receive around 5 SBD and 1.5 SP
Not that much profit... But it's something. I guess that the current state of the market does not help. I used to profit more, but now STEEM and SBD value is underrated.