google.cz is an official domain owned by Google. Of course, they're the best out there. Safe site and trusted sources for me. Be aware of the ad results. I wish there were better ways to contact the customer support/help/feedback team.
It is a great searching web site! But you have to be careful for what you are looking. It's possible to find dangerous links here, both for kids and your pc.
But yea, as a search engine it's really good
WARNING: If Google is so wonderful and trustworthy, why is it that they track virtually my entire activity on the web? I don't recall them asking my permission. If you value your privacy on the internet, stay away from Google.