personally i never relied on it for actual revision, BUT i found it good for passive revision, something to get me into the kinda 'history headspace' especially if i just wasnt in the mood
there really isnt many a-level history revision sites because of the fact theres so many exam boards and topics, and obviously at a-level history is a lot more subjective
id suggest mindmaps, fact sheets, key people/words/dates, timelines, flashcards and practice essays