Former Ohta-San owner here - the advantage is that it's just an all-around great uke! The only reason I'm a *former* owner is that the scale length, while smaller than tenor, was still too large for my tiny hands to play comfortably, and it was causing me hand pain.
What I really liked about it was that it had great playability up the neck much like a tenor does (!4 fret join and more sustain than standard concert scale) but still retained a very ukulele-like sound, rather than sounding guitar-ish as many tenors do. So I'd consider playability higher up the neck, and more sustain, to be definite advantages.