Charizard and Donphan both have their great points. They're actually quite similar - both can hit incredibly hard for only 1 energy (Donphan can hit 60, and Charizard can hit up to 80), and both of them have a sizable amount of HP and cannot really be 1HKO'd. The difference really lies in the support - Charizard gets more of it, due to Ninetales and Typhlosion Prime, it can get 1 free energy for the turn, and while you're at it, you drew 3 cards (only downside is Charizard took 10 damage). However, Donphan is a lot more of a tank - it can get set up much faster, being a Stage 1, and due to its Poke-Body it can last a very long time.
If you know what the top decks are in your area, though, that can give you a bit of an advantage to choose what to run (if there are tons of Jumpluff running around, for example, go with Charizard). Overall, though, I would say Charizard is the better deck because of how fast it can get set up - all it really needs is 1 Fire Energy in your hand.