Out of all the current meta decks, Mew Genesect is the one I'm struggling against since I can't use my usual strategy which is taking around 2 turns to KO a Pokémon VMAX or VSTAR given that Mew VMAX could simply bounce itself back to the deck. Another threat to consider is Meloetta which can KO...
I find it hard to deal damage huge enough to KO Pokémon VMAXes due to the lack of Gengar VMAX. For the most part, I always get murked by RS/SS Urshifu VMAX decks.
I'm currently running a Gengar V deck in PTCGO minus the Gengar VMAX because I ran out of code cards to trade then it became more and more expensive to get.