The best there is really. Way to go, dudes, keep up the good work! Although nasty stuff is really one click away. Still, parents should wake the hell up and pay more attention, if they don't want their kinds wandering around the wrong neighborhood.
You can easily turn off the safety search it doesn't even have a warning page like yahoo does. Once off even if you google normal terms you have a chance of seeing adult images. some examples? google "sora" you'll get results for both kingdom hearts and adult sites. Another example is "pokemon misty" if you search that under images with safe search off its brings up lots of those sites too. And when you search the real thing it does not hold back.
It doesn't install any spyware but the search engine is spyware itself, Google tracks everything you search and they also have trackers on 95% of websites so that they can see who visits what website. And don't even get me started on Google Chrome.