Both of them and, in fact you could say exactly because there are two of them. I like the keyboard sound in the TowaxSuisei cover better than the original and going for piano instead of organ works very well for the approach ChiguxHachi, so both of these covers already have a superior backing track. On the singing side, Suisei and Towa go all in on the belting whereas Hachi and Chigusa go for a softer approach making the original feel like an in-between approach that lacks the unique charm of both.
https://www.youtube.com/watch?v=0firv69LkgIhttps://www.youtube.com/watch?v=VwkxlMYpT9M 