By far coil has been the best.
Out of all the dungeons, probably have had the most fun in Aquapolis. Our FC are really enjoying doing maps again, and the dungeon itself is fun to see how far you can go
Most memorable, if it was fun or not ... was titan back when had to get Relic. Level 90 gear and had to use food with vitality as my poor Bard could not sustain the stomps, lol