What is best for others may not be necessarily be best for you.
And asking what is best usually boils down to "What CMS do you know?" With the hundreds out there, who can say which is the best?
I started in with Drupal 4.6 in 2004 or so and Wordpress about the same time. I did a long and exhaustive search (those two were a lot less dominant than they are now).
Now I still use Drupal and Wordpress. Has nothing really come along that's better? I have no idea. I know more and more about Drupal and less and less about the alternatives. Most people are probably like me.
Unless a killer feature comes along in another system or the one you like goes out of active dev, once you know a system, you tend to stick with it.
What's the best OS? I bet 99% of the people out there will pick a flavor of Windows, Mac or *nix. Ask them what other operating systems they know... they won't be able to name many let alone speak intelligently about them.