Ok, so we have playtested two matchups with Zach Fisher, a very respected player.
Typhlosion vs. Emboar, obviously both using Reshiram as an attacker. The verdict is that Typhlosion is more consistent. We played about 5 games and it was 4-1, the game that he beat me I misplayed by getting a regular Typhlosion when I really had a Prime out. If I get my second Prime out, it would have been a much more interesting game. All the other games, Typhlosion consistency and speed was just too much for Emboar. For "stat" keeping purposes he was using Shuckle. So results may vary if Emboar is using Ninetales, but probably not by much.
Then we have also play Reshiram/Typhlosion vs. Zekrom/Pachi/Shay. We played 4 games, and I didn't take a prize once as I kept whiffing on energy. So Zekrom might be too consistent for Reshiram/Typhlosion.