Welcome to what will be my last CotD review for quite a while; I leave this Friday for a 2 1/2 month study abroad trip, so I will not likely have the time to do these while out and about. Anyways, onto the review:
Cresselia MD is a decent choice to use over the GE one. Stat-wise, she has 70 HP (Good, but 10 lower than the GE version), +20 Weakness to Psychic (not good, since Gardevoir is such a big threat), no Resistance, and 1 Energy for a Retreat Cost. Future Sight is a decent choice for an attack should you be forced to start with her (obviously, you should ideally not be attacking with her until you level up) as it allows you to rearrange either your top 5 cards in the deck or your opponent's top 5. Healing Light is expensive at 2 Psychic Energy and 1 Colorless Energy for a mere 40 damage, but it does allow you to remove 1 damage counter from each of your Pokemon, potentially saving some from being sniped and KOed. It can also be used I guess if you're weakening something to finish them off with Cresselia Lv X's Moon Skip.
Overall, I feel she is a better starter (once again, if you have to) despite the lower HP, as Future Sight lets you either give yourself an advantage or to mess with your opponent's start. The GE version, however, is better with its attacks for supporting its Lv X form. In the end, I guess it's really up to you though as a player to pick what one you want to use.
Modified - 7/10 (Solid Pokemon, meant for leveling up though and not for attacking by itself).
Limited - 7/10 (2nd attack is expensive, but heals your Pokemon. Future Sight is great for getting an advantage in setting up)
Unlimited - 1/10 (Why would you use Cresselia here?)