First, I agree with you, I think Barwin has the potential to be better than Cushing and Matthews.
Right now they have more momentum, so they are rated higher and will go a round before Barwin, but that doesn't necessarily make them better.
Second, it is not a "fact" that they tested positive for steriods. Yet. A blog site reported that they heard it and several other sites repeated their claim. No one has confirmed it outside, only repeated that there are "reports" of such a positive result. One site has since taken DOWN that webpage, which makes you wonder if it's true.
http://www.saintsreport.com/forums/showthread.php?t=106503&page=11
http://bleacherreport.com/articles/149917-cushing-and-matthews-test-positive-for-steroids