Earlier this week I compared the results of GP Quebec to the MOCS Championship that occurred simultaneously and pondered whether Mantis Rider or Siege Rhino would come out on top. A quick stop at Channel Fireball this morning shows that LSV and Reid Duke are calling Dark Jeskai both the best and most popular deck.
Last weekend, at GP Quebec City, 8 of my 13 opponents were playing Jeskai. This weekend, anyone who wants to do well in a Standard tournament should be prepared to face Jeskai—specifically Dark Jeskai—in at least half of their matches. And I expect this trend to become even more extreme as the format matures.
Jeskai is the real deal. I wasn't going to go to GP Indy this weekend, but after playing Jeskai on MTGO, and seeing the GP Quebec results, I booked a ticket. I'm going to play Jeskai, and am looking forward to battling mirrors. If you haven't practiced a lot against Jeskai, you are going to be in for a rough Standard season (though I suppose you will get that practice, one way or another).
You were probably already ready to battle Mantis Riders this weekend, but maybe an extra sideboard card or three will come in handy. Going into this weekend the race between Siege Rhino and Mantis Rider looked too close to call to me, but these guys aren't exactly slouches.
I definitely suggest giving Reid's entire article a once over for some dos and don'ts of beating Jeskai. It could make all the difference at GP Indy or SCG Dallas.
From a financial perspective, I suggest targeting prospective adaptations for the deck as the mirror becomes more popular- assuming that the metagame and results are reflective of Jeskai being the official boogeyman. I'm also quite positive that Ojutai's Commmand, a mirror and format-defining card, has room to grow.