It's actually the opposite reason for me....
Not really because they looked more like real clothing, but... even though Merveilles had some really beautiful costumes, especially Gekka, there were always parts I didn't like as much.
Közi's ILLUMINATI and Cyberland costumes, for example. The Cyberland outfit and makeup didn't go together, in my opinion.
So, in the end...
Most extravagant: Merveilles
Most normal looking: Memoire
Favourite: Beast of Blood, Shiroi, Gardenia, Saikai and Kyomu