The only difference that I find is I can call folks at Epic or Huntinfool and talk about units not mentioned as the best in a state. Sometimes they have really good intel, other times they don't know any more than I do already. Eastmans is in the middle between gohunt and the other two, IMO. I like Eastman's articles, so they have some added value.
It's all in how you use what they offer. If you want the top units and kind of generic info, gohunt and eastman's are about the same. If you want to talk to a human, the other two are better.
That said, talking to a biologist in the unit you are interested in is more help than any of the above, IMO. It really comes down to what questions you ask and how you use the info. I typically use Gohunt to get the units I want to research, then use the phone to narrow that down for my applications. I could do the same using info from the state websites, but the draw odds tool is too easy in GoHunt even if it is only a ballpark in some states.
Jeremy