You have come to the same conclusion I have. Paying for resteems isn't worth it. I think this largely due to most members here on Steemit don't bother checking their own feeds that often. Some of these resteem services simply follow thousands of steemit users and in return a portion of those user follow back but never check any content from said user. Take a look at how many people some of these services follow in relation to how many follow them. If the number they follow is higher then how many followers they have its likely they applied the above strategy.

I recommend using free resteem services. They seem to work just as good.