This depends on what you are interested in learning and how seriously you take magick. Most of the covens offer a little of everything, but you gotta find the one that suits your interests. A few of them are open to public viewing, which you can see by clicking the [FORUMS] tab and then [COVENS] (next to ''newest''). Read through those and see i any fit your interests :)
Or you can click the [GROUPS] tab at the top and read through the coven descriptions.