Jeskai Black was my pick for standout deck from week one of new Standard, but after two consecutive second place finishes and a trophy on week two, G/W Megamorph has made its presence known.
I wrote in my insider article last week that Siege Rhino has lost a lot of appeal with rotation, and the success of G/W Megamorph is a consequence of this. It wouldn't be very difficult to add black mana into this mix, but instead the Megamorph deck fills up on resilient threats and creatures that generate value.
It's also worth noting that G/W Megamorph is arguably the best shell for Nissa, Vastwood Seer due to the deck's ability to play a higher volume of basic Forests. In light of this, you're likely to be able to find a Forest with every Nissa that you play in a given game.
G/W Megamorph will be public enemy number one going into the Pro Tour, and it will be interesting to see how the various pro teams approach this position. The deck has many of the qualities of a typical "best deck", and it's certainly a safe choice to just pick up and jam. Alternatively, in a format with great mana it seems likely that any best deck can be dethroned with clever enough deck construction.