As a journalist and journalism educator, I would not consider ANY source to be unbiased. Every person has biases. Every organization has biases. Sometimes the bias is obvious. More often, it is subtle and complex, and so it may be hard to see.
Each Wikipedia article can have many authors and many editors. That should help to remove all biases -- but human nature doesn't work exactly like that. It's always possible that all the writers and editors on one Wikipedia article shared similar biases, and if those are subtle, they might be hard to detect.
A good journalist will always check any fact or assertion with at least two sources. Many Wikipedia articles cite reliable documents (with links), and each one of those might be considered a source. But a good journalist will also check with some other person, original document, book, institution, etc.
If you don't check it carefully, don't be surprised if you turn out to be spreading false information! This is not a fault of Wikipedia -- all data are suspect until they are checked against multiple sources.