Yahoo is Number one website in the world according to alexa.com and i think yahoo has Huge service more than Google , but Google has great service too but not as much as yahoo .. Google search is Easier and better than yahoo . i think we can not live without Google or Yahoo we got to have both ..
I strongly believe that Google is much accurate results than yahoo. It has got great goodwill in search terms. So Google is the best.
Yahoo mail and yahoo messenger are better than google. Google search engine is better than yahoo. It's really up to end user which one he prefer