Google is much better than Yahoo, imo. I'm using Google last 5 years and never had any kind of problem.
Google is better in terms of search, I will give them 50 - 50 in terms of email, just like somebody mentioned, I think they are both needed and useful
I think Google.. Google has more innovation of technology and always improve their search rank calculating...
according to me google is not only better in terms of richness than yahoo but also in terms of the services it provides.
Regarding internet marketing I can say that Google is one the king of the internet marketing. Research shows that 75% of the internet is marketing is done via the Google. So I can say that Google is one of the best search engine in the market.