I was debating the blackwidow too however after looking at some reviews alot of people are complaining about the QC of the keyboards they are getting - keyboards failing after 30-60 days, keys getting sticky, hard to clean and the backlighting failing.
I can't remember the exact terminology for it however the blackwidow also suffers from 'ghosting' or 'anti rollover' where as there are alot of keyboards at the same price range who have eliminated this. There's a link below which describes what ghosting is.http://www.microsoft.com/appliedsciences/antighostingexplained.mspx
Edit: Just re-read your post and noticed you already mentioned rollover. Sorry about thhat!