Commie: If there is a Horrible release of a title, Commie will probably do a Modified-CR.  If there is no Horrible release (meaning no professional script available), then Commie will do their own translation.  In this case, I didn't see any note at Commie's on this title .  I'd say 60 - 80% of their releases lately have been Modified-CR.  Sometimes that means Horrible + OP and EN + Hi10P; sometimes it means more.

Rori has more of a reputation for doing their own original translations, such as is definitely the case with this show.  I don't recall hearing of them ever doing a Modified-CR.  The downside: They will fall behind the weekly release schedule rather quickly.  I think they just released ep8 or 9 of the 12 part "Shining Heart" from last season.

As to your question, you might prefer the style of either version with differences possibly in things like honorifics, or how western things are made to sound, or who knows what; both will probably be reasonably true to the text; you might prefer the idea of a true fansub translation.  If you like the series, try both for an episode or two.  Most people like the weekly new episode idea, and will probably jump ship when Rori lags, planning to watch their version later.