Google's DNS service: Google public DNS

Google declared their free DNS service, Google public DNS:

To try it out: Configure your network settings to use the IP addresses 8.8.8.8 and 8.8.4.4 as your DNS servers.

They claim that:

By using Google Public DNS you can:

• Speed up your browsing experience.
• Improve your security.
• Get the results you expect with absolutely no redirection.

What do you think about it? Should I use those DNS servers? One reason to use them is I cannot open the web sites banned by the government (such as YouTube!).

Solution 1:

A quick comparison of Google Public DNS with OpenDNS (which has been around for a long time).

If you have to access sites banned by Google DNS (or, OpenDNS for that matter), you can skip these configurations when you hit a problem. However, most of the time sites blocked by OpenDNS (and, I have to still look at Google Public DNS more) are those which I would never want to go to.

Update based on your comments on YouTube in other answers.
If YouTube is really banned by your ISP (or higher authorities), changing to another DNS will usually not help (unless this 'ban' is very weakly implemented). You would need to investigate tunneling techniques to bypass such bans.

Solution 2:

Using google as DNS would mean they will see ANY DNS search or in other words they would know about any site you (likely) went to and so you provide them with a LOT of somewhat personal info, which they could collate with the other info they gather on you, make sure you are fine with that and be aware that if the law changes or there is some subpoena they could then be handing that info over to authorities who as you know will 'use anything you say against you'.