Tor is not perfect and everyone would be wise to learn as much as possible about its limitations (I'd start here: https://www.torproject.org/download/download.html.en#warning). It's still a very useful privacy tool though.
Snowden: "I think Tor is the most important privacy-enhancing technology project being used today. I use Tor personally all the time. We know it works from at least one anecdotal case that’s fairly familiar to most people at this point. That’s not to say that Tor is bulletproof. What Tor does is it provides a measure of security and allows you to disassociate your physical location."