When it comes to TV ratings, CBS and Fox are slugging it out for top honors. But Murdoch’s net edges the Eye web when it comes to employee 401(k) plans.Financial information firm BrightScope rates thousands of company retirement plans on a scale of zero to 100, including those of the four major TV nets. News Corp.’s Fox plan is at the top of the heap with a score of 78. CBS follows closely in second place with 77. Disney (ABC) comes in at 74, and Comcast (NBC) trails at 71. Brightscope says it seeks to bring “transparency to opaque markets.” Its ratings are based on six criteria: total plan cost, company generosity, investment menu quality, participation rate, salary deferrals and account balances. Three of the four plans get top marks for lowest cost to employees. News Corp.’s plan costs are not quite as low (although it has “low fees”) but it scores best on participation and deferrals. CBS had a “poor” rating for its investment menu, which probably cost the plan the top spot among TV nets. Some companies have multiple plans, and News Corp. has a separate 401(k) for its News America unit. That plan has a rating of 71.