>>542041873
I'll preface saying I don't dislike any of the 3.
I think Teogonia suffers from being the first and having the most tanoshii party SoL part of the story + few characters.
Gehenna is really good but the staggered releases make it hard to judge its world setting versus the events which paint stories set within it that make you curious to learn more.
Niflheim is recent but I was left more than satisfied with every single character from it, so I'd have to go with it.