I was interested in whale roi for the main bots over a curation cycle its interesting that randowhale and minnowbooster are not listed for the calculations. I also find it interesting that each tag has a weight that is a good handle on the requirement to appear in the toplists.
That said quality is king in the longrun building the reputation and following and that is where the real worth begins and the bot's become less useful you need to pay to get there but once its built your set.