I wrote two posts on Bid Bots a few weeks ago and I planned to continue the series. You can read the first here and the second here.
Meanwhile, a lot of changes happened and I wanted to wait for the outcome. For this reason, I decided that I try to give you a very brief overview of the current occurrings. I will share my opinion at the very beginning: the road to hell is paved with good intentions...
Q: What the hell is minimum ROI?
A: ROI stands for Return On Investment. It indicates the relation between the upvote value of the Bot and the bids sent. If a Bid Bot has a minimum ROI that means that it prevents significant overbid and losses. If the minimum ROI is less than zero (in case of almost all the bots) there is a chance that the received upvote will be less than your bid was. The higher is the minimum ROI the less is your risk.
Q: Who will benefit from negative ROI cap?
A: Who sends the bid. But frankly, minus 40% ROI is not that lucrative - only for a bot owner.
Q: What is maximum ROI?
A: That sucks. A maximum ROI means that it does not matter how many bids were sent to the Bot you will not get a bigger upvote for your bid than the cap allows. 10% cap means that if you send 1 SBD you will get an upvote maximum in a value of 1.1 SBD.
Q: What the fuck? Lots of upvote value will be lost! Why was it introduced?
A: It was introduced because of jerks who created bullshit content and bought upvotes and gained profit. By a great timing, they got on trending page, which is the 'holy cow' of steemit.com. By the way, I don't mind the last, it's still full of shit and I hardly visit it. The expectation was to prevent raping the reward pool by shitty posts and using the Bid Bots only for being detected.
P.S.: There was a side effect and not an ulterior motive, I hope at least. The majority of the Bid Bots always vote when their voting power reaches 100%. After voting, it takes 2.4 hours. If a Bid Bot works with an ROI cap, it will not use its 100% of voting power in a voting period. That means that the voting period will shorten and the bot doesn't have to wait for 2.4 hours. Outcome: instead of 10 voting periods a day the bot can have 12-16 a day. It is a good question, who will benefit from it...
Q: What is a maximum age limit?
A: It's an old story, 
Q: Why is then a minimum age limit? I wrote a nice post, I want to promote it immediately.
A: It's about the profit again. If you upvote a post, you will get curation reward. But as far as I know, the curation reward permanently changes in the first 30 minutes. If you get an upvote in the first 10 minutes after posting you will get the full upvote value when your post expires, there's no curation fee for it. The closer you are to the age of 30 minutes the higher is the curation reward. If you get an upvote after 30 minutes, 25% of its value goes the curators. That's why many whales self-upvote their own post at the very beginning. It's clear, that if you manage to buy and get an upvote from a Bid Bot in the first 10 minutes you can make a profitable bid and it is here the pure devil.
P.S.: But it has again a side effect and not an ulterior motive, I hope at least. Because of this 'minimum age' rule, the bot will get curation reward (profit) from your post besides your precious and valuable SBD/Steem you sent as a bid. And it is not for your benefits.
This post reflects my own experiences exclusively. I'm not a bot owner. I don't take any responsibility for your loss by using upvote services. It is your money, your decision. My suggestion is to use Upvote Bots for promoting your post to make it visible to the community or expressing your gratitude for a good post of another author. I also would like to draw your attention that there are communities on steemit.com who reject the Upvote Bots completely and started a crusade against them by flagging posts promoted by bots. You can get in their crosslines easily if you use the services on your posts especially in the last minutes.
Should you have remarks or opinion on the topic, please leave a comment!
@gabeboy