High-grade copies of Rocket's Mewtwo are hard to come by, and PSA 9 and PSA 10 examples command prices that place the card firmly among the most valuable vintage Mewtwo printings in the market
From what Ive noticed, the proofs that have detailed drawings on the back normally sell for significantly higher than ones that are just signed or blank
You cant counter this, and most removal will be instants or sorceries, so the Niv-Mizzet player is still up a card
Cards like Wound Reflection and other amplifications cards will help to get you the win, and considering the card advantage Kefka gives, you can run combo wins pretty reliably
Over time, this enchantment locks down hands and chips at life totals, especially nasty when paired with The Haunt of Hightower to grow stronger off every discard
Top stores in the TCGPlayer Direct program will have the opportunity to be part of the buylist program, and it will essentially create a marketplace for buylists similar to what is currently available