Having been defeated by two different Sagas, in two different games - Rite of Belzenlok being one of those, I can tell you that Sagas are crazy powerful cards that require your opponent either to take them out as quickly as possible or save up a removal spell for the giant creature some Sagas spawn as their last act. Pretty decent Rare pulls, nothing extraordinarily valuable - in money terms - but a lot of them will work great in a bunch of casual decks - or Cube, of course.