Well, I"ll tell you--hours after we acquired Kelly Washington, I went to Wikipedia to see what it had to say about him. It began by saying he was a wide receiver recently signed by the New England Patriots. This was only hours after it happened.
Wikipedia is not perfect--neither is the Brittanica or any other written source. All are written by human beings with points of view. Sometimes, the points of view lend insight, sometimes they are biased, and this is most certainly true of Wikipedia. When there is controversy, you can find Wikipedia discussions that include different points of view.
And sometimes, like all other sources (with the possible exception of the Bible), it contains actual errors. Thanks to the 75,000 people who regularly contribute and vet Wikipedia entries, these are usually self-correcting, which is something no other encyclopedia can claim.
I've found that except in the case of controversial subjects, Wikipedia is pretty reliable. If you doubt what it says, it will lead you to a variety of other sources. It's a fine way to begin your research, and it's usually quite up to date.