CBS >> Yahoo, imo.
That said, I've been using yahoo for my league the past few years. This year I recommended changing to CBS or MFL. But when I saw Yahoo's new prices, it was just too good to be true. $30 for the entire league and that includes free Stattracker for every owner. CBS premium makes sense in a high stakes league, but in mine, with $80 team fees, the payout is near 95% after Yahoo's fee. It would be much lower had I chosen CBS.