Charizard the first fire type and one of the top three best starters. It has high speed and special attack and exceptible attack to make him an awesome sweeper. He also has a great move pool.
Magmorter has high S.defense and S.attack making a good tank. he also has a decent move pool. also he has a pretty good ability.
Charizard is cursed with a 4x weakness to stealth rock. Charizard has high special attack but his best moves are physical.
Magmoter when I said high S.def I meant in comparison to his other stats he has bad defense so flame body is hard to take effect especially with earthquake being immune to flame body.
So I would say Charizard is the best.