Well i think its not really worth putting double collerless energys in a deck no more because of lthe card lost remover. When you attach a dce you usually heaviley rely on that energy card. So when it gets discared it really hurts your game. But other special energy card arent so bad because you dont rely on it so much.
The the best time to attach a dce is when you can discared it right away. Like for example zekrom ex second attack. You can discared it right when you attach it on to zekrom.
If mewtwo ex gets a double collerless energy discared from it' it's not that bad most of the time.
What do you think?