There's no single card that completely dominates (other than the Pikachu HR), which means several cards are trading in a healthy mid-range that makes collecting the full SIR set actually achievable
Honestly, this is true for all difficult decks to play, and for all players (I am on week 2 of trying to learn to play Leviathan optimally even though it quickly became one of my favorite decks and taught me worlds about water control as a whole for other archtypes)

X is fun...I had a lovely deck with it that I might revive with Ninetales (HGSS), that I had considered when first I heard about the Ninetales I think I will have to go with Ray-CX for being, and I'm a Ray fan, but after trying to build a solid deck with it, considering it is to be a main attacker, it's just too difficult to be able to consistently either have no hand, or to constantly load energy every turn Char-GX would be my next choice, 5 energy consistently, and not that grand hp, binder bait for sure the rest, I don't really have all that much of a problem with...Dialga is too fun, it's just meant as a fun tech anyway...Rhyperior is a beast when used correctly, but is difficult to pull off some X's were meant as techs, some were meant as attackers, outside of the 2 that I mentioned...the rest aren't that bad at their jobs, imo Soul Urusai Urusai Urusai #15 dragonexpert said: If you get power sprayed you get to do whatever else in your turn, unless I am mistaken

Lastly, Black-White is a reanimator deck