Yangs is a breeze though. It's so easy to power level in that place. Then you can easilly have both him and Ursula one shotting everything in that place. Those two are beasts.

Rydia's is simple too once you learn Bio and know the path to take. So after one or two runs, you'll be aquiring rare items in no time.

I've completely finished Yangs chapter. Obtained all the bonus dungeon rare drops, and even got that damned Red Tail. Just need to power through Rydias dungeon a few more times to get the Adamantite, Sprint Ring, Gold Hairpin and Black Robe. To bad the last chest isnt' a guaranteed rare Item like it is in Yangs.