Depends on your need if you target great audiences by help of those famous name in forum then they are really an best option. But since they are special pick expect to give them huge reward since if your offer is the same with normal campaign only then you provably cannot get their services.

But I doubt you can easily get the service of Charbuddy,JJG,franky1 since I don't see this user wearing sig and promoting other company for long time. Maybe you will need a good convincing power before you can make this people agree to your offers.

If you want to try other more then try to hire a campaign manager then let them do the job for you for sure a manager would help you select those best forum poster that can help you promote your site.

This is good campaign managers in forum

Little Mouse
icopress
Hhampuz
AB de Royse777

This 4 guy in the list is best manager to handle your campaign so choose wisely.