I've been getting promotions from some of these services, too, and I'm new to Steemit. I'm not here to make money, that's just a bonus if it happens :)
But would this be worth it to boost my following? My main reasons for joining were to write and be heard, to get my stories out there... But I don't want to invest in that if it's mainly bot votes or something similar..
@resteembot is the only one worth the minimal steem they charge in my opinion, and it gets viewed by a lot of new users who have recently joined. The others are good too, but the number of views and upvotes isn't worth what a lot of them charge in my opinion. Using @randowhale and @minnowbooster to upvote your posts are good value, as you usually get more back in upvote than the 1 SBD you pay.
I'm pretty new to Steemit, although you may recognize me from Facebook...
But I'm still trying to understand how this whole steemit thing works myself.
What I am noticing is people who are desperate to make money on this platform, are trying every trick they can, only to end up going nowhere. While those like yourself, who are just here to share intelligent creative content, are the best rewarded in the long term.
Just post as much original engaging and informative material as you can, and don't stop.
Hope that helps , eh.