i got her on her first released, when i came back playing she already have EX.. my question is did you guys get her mindsphere as well on her re release event?
Unit's strength: Meriluke is better. TMR's quality: Etre is better. Easiness to enhance: Etre is better. Then you can decide which you take.
My simple advice is that don't think too serious. On the JP server, my Meriluke is lvl 99, but I still have enough resources to max level Etre. It just requires time though.