Yahoo! Finance is probably the last respected Yahoo product on the market. The serious investors I know always use Yahoo Finance as their free data source (they also have expensive private data sources, of course).
Plus Yahoo Finance makes it super easy to download historical closing price data in CSV format to do your own analysis.
So does google actually.
No the Google Finance download feature is far worse, and effectively useless for many types of analysis. The data only goes back to 2000, whereas Yahoo goes back to 1986. And the Google closing prices aren't adjusted for dividends which makes it impossible to calculate actual returns unless you pull that data in from another source. Yahoo includes a separate column which has that built in.
Thank god they rolled back the terrible beta redesign.