I think it was pretty great, but I'd have to say FFIV or VA's bonus dungeon was the most fun to me.

However, since I like keeping my characters at relatively low levels (not extremely low, but not in the 50s or 60s like everyone suggests for some reason), and I didn't feel like spending too much time slaughtering Cactuars with my weaker characters, most of the dungeon was spent with my main party with Mog, and the other two using Teleport Stones/Teleport to avoid all avoidable battles. But the dungeon exploration itself was great fun, and so were all the upgraded dragons.

I even found a new room that I didn't find in the Japanese version! I do very much enjoy discovering new things.