Still love my Legacy Chocobo simply due to it's exclusivity (and it has the Legacy mark on it's beak, the same mark my character has on her back ).

My main go-to mount is traditionally the Griffin though, as my character is Ala Mhigan headcanon wise so it makes perfect sense. That and how well it's animated in flight and on the ground is just superb.

Lately however, I've had a preference for Argos, even ignoring his story importance and connection to a certain important... person (and the big spoiler in his mount description), it's just right - I love his unique BGM and additionally, as my current glam is the Ancient robes (Sophist gear), I can't think of anything else that fits the image. Also there's nothing like zipping around the world on the back of a flying radioactive dog.