I think Google has gone that far in fighting spam that their results are gettings worser with every update. (Also their link rating was once a good idea now has turned against them due SEO.)
Yahoo is quite better with results now do they haven't overscrewed their system till now. (It can not be wrong to rate good for text and header text and url text ... this is simply how the web is intended.)
Yahoo yet looks to me like Google before 2 years before getting worse.
(To really get it much better you may need some human component in - like some rating buttons in the SERP.)