I am not sure about other posties of PayPerPost but recently, I found that it is so much easier to make paid posts after PayPerPost asked for disclosures. Some bloggers tried to do it with different font colours, some placed a button to indicate a paid posts and some put the sponsored disclosures at the end of their posts.
For me, I am just going straight to the point by typing it with an *sponsored*. Once I got over that first line, I found that I can just talk about the sites or products I am writing without having to beat around the bush.
Therefore, I found that it is good to make disclosures because one has no hang-ups about giving a complete review.
So, I am really glad that PPP requires posties to make the disclosure.