Well from a Stat point of view there is nothing different, since these two starters have the distinction of having the EXACT SAME BASE STATS. xD
In comparison to movesets Typhlosion is one of the small group of Pokemon who get access to Eruption and coming off a base 109 SpA, it's going to hit pretty hard.
Typhlosion's sole Fire Typing gives it less weaknesses than Charizard's Fire/Flying. In Moveset Terms, Charizard ia lot more versatile with STAB Air Slash and moves like Dragon Pulse and Fire Blast to back it up.
In an ingame strategy, I'd pick Charizard, just because more moves = more super effective = more yay xD. And Charizard is just pure aweosme ;o
In a competitive standard Typhlosion and Charizard aren't too different in my opinion. Typhlosion's awesome eruption gives it an effective niche. Especially something like Choice Specs Typhlosion in Sun. Everything dies. However in the same token, Charizard's ability Solar Power evens up the odds since it increases SpA by 50% (A choice specs boost) at the cost of some health each round, and roost gives it extra longetivty. However its Stealth Rock weakness leaves a little to be desired. So in a competitive scene I'd say just choose which one suits your team more, since most of Typhlosion's power comes from Eruption, if you have a reliable way of healing go him, but if using Charizard a rapid spinner is basically mandatory to get it's full effect.
Also forgot to say this but Charizard can run an effective Physical attacking set with access to moves like Swords Dance, Acrobatics, Earthquake and Flare Blitz
Typhlosion @ Choice Specs
Ability: Flash Fire
EVs: 252 SpA / 4 SpD / 252 Spe
In this set. Eruption. Choice Specs. Enough said. :P
Charizard @ Heat Rock
Ability: Solar Power
EVs: 4 Def / 252 SpA / 252 Spe
Sunny day boosts Charizard's offensive prowess and Heat Rock increases the duration
Alternatively if you run Charizard in OU with Ninetales Drought (this is a dumb thing to do and don't do it since Charizard is outclassed) you can run a full attackign set of Air Slash or Roost /Solar Beam/ Fire Blast/Focus Blast or something like that