Acacia will not be able to get 25% of your income if you don't get most of your income from something related to their bogus patent. That is just them dreaming. You are better off dealing with a court and having the court set the amount of money they will get. Also, there is almost no way a court is going to give Acacia access to your books.
Those are just scare tactics. As long as you are willing to fight, even if Acacia keeps the patents, which very few people think they will, you will still get a better deal by fighting them in court.
The people who have already signed are either stupid or they negotiated a much better deal so that Acacia can issue a press release saying they made some deals and try to keep their stock price up.
This link has been posted many times on GFY, it is the actual package that they send to people:
http://www.afrochicks.com/info/acacia/index.shtml