I have and personally don't like them.... it waters down the entire FF experience. Too many players that are not stars that can gang up and contribute to a W or L. You can literally watch NFL Primetime... dominate teh highlights.. and lose b/c a crew of 2nd tier defensive players gang up for 4 tackles each adn take your team down.
Plus, there are a ton of defensive players to be had off teh waiver wire. So pretty much stick to drafting offesnive players adn then have a quick trigger to scoop up solid-middle tier defensive players off teh wire.
BTW, for those interested, I noticed fantasysharks.com has IDP article / rankings:
http://www.fantasysharks.com/artman/pub ... e_1566.htm