I find this card quite intriguing. It's not the best, being pricey as it is, but it's certainly not the worst. 2 energy to attack for 50, 3 energy to attack for 30x depending on how many fighting energy you discard, and 4 energy to attack for 80 damage that laughs off resistance. Retreat is horrible, weakness is workable, and resistance is useful. This card really needs it's own deck and, more then likely, DCE to work to it's fullest potential.
What i'd use is Golem AR, Groudon LA, Sandslash SV, Rhyperior Lv X, and Flygon Lv. X. Groudon for the early energy attachment, maybe add some Unown G to stave off Machamp SF, Sandslash to keep the hand filled with fighting energy, Rhyperior to recover the energy and offer another win-condition to the deck, and Flygon to give them all free retreat and offer another win-condition to the deck. The deck should also have Palmers/Night Maintenance, Volkner's Philosophy for extra card-draw/energy grab, Warp Point/Switch for obvious reasons, Bebe's and Rosanne's for obvious reasons, and any other thing one can think of that seems fun and useful.
By itself, an easy 6/10.
In it's own deck, and easy 8/10.