Are Wikia's a reliable source?

?

YES!

They are relatively reliable, it generally depends on what sort of information you are looking for, and the depth of context you are also searching for.

@SC: Agreed!

They're good for general information, not for details.

Yes!

They are good as a secondary information source, for brushing up on various characters, when it's been a while since you've read any comics with appearances of those characters.

As a primary information source, it's good for a general outline. As long as you keep in mind that they might have errors, or just plain lack information.

The comic vine wikis are

At times they are, but they often mess up with details.

I find anime wikis to be very helpful when I need a quick bit of info on a character I don't know.

Some of them like to make shit up though, like marveldatabase

The Comic Vine wiki is due to its high moderation. I don't know how well moderated others are though.