Tier 1
TPC Comments
If you plan to win MCS, playing Harpies is the best choice. You have good matchups against the currently-tiered decks and can even make the matchup better through your Side Deck. As long as you get to set up your Loading... with backrow, you're already in the driver's seat.
Harpies continue to be the best deck of the format despite not being able to play Harpies' Hunting Ground until the balance update implementation. The main Skill being ran right now is Mind Scan , where you ideally set multiple backrow and play through your opponent's by popping the right cards with your Loading... . The deck doesn't have any bad matchups right now and is expected to preform very well in the MCS.
Harpies remain Tier 1 and is projected to continue doing so after the skill changes are implemented. Despite being generally agreed as a Tier 1 strategy, Harpie has also exhibited low uniformity in lists. With consensus low and deck-sizes high, the optimal approach to the deck is uncertain and provides the most room for deckbuilding decisions. A consequence of this situation is that the matchup spread of the deck is unclear and opinions are as varied as builds are. As time progresses we are likely to see lists centralize around a singular approach.
Tier 2
TPC Comments
Abyss Actors remain in Tier 2 for another week, with Harpies' Hunting Ground still out, the deck can play against almost anything as it doesn't suffer from interruptions. The deck can play slowly, pay life with Loading... , and get the card you need with Destiny Draw to finish games (like Loading... ). The biggest problem this deck has is its fragility against Loading... (and especially against Loading... ). Many players are adapting and using Cosmic for the Abyss Actor matchup, as they can not only banish Mellow Madonna but also get rid of Loading... in response to a Loading... or Loading... .
The first Pendulum deck that can finally compete consistently. If you are a believer of "Pend Best Deck", then you can easily outgrind and defeat your opponents with Abyss Actors. If you draw the combo pieces to play the game, then you are almost guaranteed to win. That being said, the deck is still vulnerable to backrow removal. Just pray that they do not open their Loading... .