Currently the only way I know of favoriting a magazine is via the excellent Kbin Subscriptions Panel userscript. The pen icon can be used to edit subscriptions and star magazines, after which they will appear at the top in the subscriptions panel. Quite handy!
@losttourist I don't think you can - just posts. That favourites view shows all posts you've favourited (upvoted). It's a good way of bookmarking until we get actual bookmarking.