Yeah I'm a bit surprised at the popularity of the Saga and POD quests. Its interesting to see a lot of people seem to like the Dwarrowdelf cycle a lot. My least favorite cycle in terms of quests is Mirkwood, followed by Angmar Awakened. Maybe because they are still new and haven't really sunk in yet, but so far the new cycle doesn't seem to be too popular.
I base my answers off how well the scenario is put together in terms of thematic consistency. By nature of being pulled straight from the source novels, the Saga ones fit neatly into that criteria. And since the GenCon quests don't depend on encounter cards available in prior deluxe expansions like the AP's do, they also trends to feel more consistent and well-thought-out. I prefer quests that can leave you feeling like you got immersed in a story and not in a puzzle.
Road to Rivendell probably doesn't work as well as some other quests by that logic, but still for whatever reason it is my absolute favorite.