I've had this discussion with a friend. He wanted to bring Emboar to Worlds. Bad choice.
Typhlosion is excellent in pretty much every situation, whether you're winning or losing. After something gets slaughtered, not a huge deal, you can get the energies back. If your board is looking pretty good, then you can just load up more stuff for later. He also gets rid of Rescue Energy, which is amazing in some matchups.
Emboar is nice for early-game shenanigans and loading up stuff quicker. But if they pull him forward, you're done. Getting 4 on him for 80 is a bad joke and you have no way to get energies back. Retreating him for 4 is even worse. And after an opponent's Judge, you probably won't have 3 energies in hand to keep loading up that Reshiram. Typhlosion wins here as well.
Overall, I don't even know why there's a discussion. If you want a chance to donk, play Emboar/Reshiram. If you want a good deck, play Typhlosion/Reshiram. But then, even if you want to donk, you should've gone for T1 Zekrom instead.