Cyclone Energy is an interesting Energy card, and became somewhat of a tech in decks like Gyarados to get around some of its counters.
It is one of the more practical ways to get around Locks brought about by techs like Spiritomb AR, Mr. Mime MT, Shuckle SW, and Shedinja SV. However, if the opponent has 2 of those Pokemon in play, playing Cyclone Energy is somewhat moot. Still, Cyclone is also handy to get rid of effects on the opponent's Active Pokemon, some notables include Flygon RR's immunity from Sand Wall, and Garchomp SV's defense boost from Guard Claw. It has some disadvantages against cards like Poke-Blower+ and Pokemon Reversal (since you can't choose the Pokemon to switch). However, Cyclone Energy's strength lies in it being able to be played out of nowhere, especially since Poke-Blower+ and Reversal can be stopped by Trainer lock.
All-in-all, though, a somewhat situational card, but can be surprisingly effective in the right situations. It doesn't have the luxury of being immediately spared a slot in most decks because of the all-around usefulness of other Special Energy cards, but if you have the space, it's not bad to include at least 1.
Modified- 7/10 (a nice anti-Spiritomb tech but situational at best since DCE, Call Energy, and even Warp Energy usually gain the slot for Special Energy cards in most decks)
Limited- 8/10 (can provide some nice disruption and can help get around stalling tactics like Agility, Harden, etc.)