I am looking at the website steembottracker and who has less investment and whose upvote value is higher the time is very important in bid for bots. Because more the investment comes hen it will be distributed less and it might get you less upvote on your blog.
I prefer many bots like @whalecreator @sneaky-ninja @whalepromobot @upmewhale @smartmarket i prefer this bots and looking at the ROI it has best ROI and it also does not give upvotes in 7 days as some of bots are very lazy and gives upvotes in 7 days of time and this 4 bots are regularly giving upvotes and they are less invested with good Steem power and very populated account so i prefer this bots for my post to upvote.