Don't really know if this is allowed but...
Zero would win. His speed and skill have power over X in every way. It even says in the first Megaman X game that X wished to someday become as powerful as Zero.

Local Mods : A&B 
To answer i say ZERO ENOUGH HE IS EPIC  

Zero is better then Megaman especially X because of his superior dashing and jumping abilities and the fact that Zero did beat Megaman (copy X) before in the Megaman zero saga. Also I choose Zero because of his superior arsenal of weapons like the saber the b buster, the shield and the batons.

Magma_Cube : I know "X vs Y" threads aren't allowed but due to not alot of activity in this forum and I don't see a problem with this thread that could result in spamming or any other major rule break, i'll allow it to stay open.

Divine Aurora : Thanks For Letting It Stay Open. And Yeah Zero Is Overall Better Than X. The Sabre Has To Be One Of His Strongest Weapons And If Not That Then His B-Buster. 

Now i'm a big fan like you, TheGameLegend, Zero is my main man. However, if the battle had been more epic in X5, I would personally say that the battle would've been a complete tie. Its "Greater Good" Vs. "Greater Evil" so to speak. The only way for there to be balance is for both to live or both to die. I'm honestly stuck between them. They are both unique Reploids but Zero's tie to the past and the fact he is the tragic hero in the end makes me love him all the more. Nothing against X though, at all. 

I personally like to base it on this awesome animation but that's just me: http://www.youtube.com/watch?v=McjxOBZrmoo

If I must choose, it will be Zero, for the fact he's the tragic hero gone Maverick in the end.

TheGameLegend : No.It is the air slash from X5 or his cannon from X6

I have only played mega man x, but zero destroyed himself, I don't think he would've been able to defeat sigma and if he could then why drag x along if he was really so weak ?

I'm responding for the games, not the characters.
And of the two games, Megaman ero takes the cake. No contest.

zerothesaint : I'm gonna be honest, for me Megaman used to be my favorite. He used to be the greatest until Zero came along, basically it's the same thing that happened to Sonic The Hedgehog when Shadow came along. Everybody loved Sonic but then when there was a new hero (And villain) who looks like Sonic but even better, everybody loved him. Megaman used to be most peoples favorites until Zero came. Overall (This is my opinion) Megaman was quite better than Zero, Megaman has the best cannon, best suits and the best armor. I think people loved Zero more because of his blade and appearance while Megaman who does not look as cool as Zero actually has some better items than him.

zeross121 : X isn't weak.he is prefered by the most.
ThaGameLegend : Zero can kill Shadow.
And congrats on beating me.you like zero more than i do .

Magma_Cube : I actually don't like Zero i prefer X I'm saying if zero was so strong then why bring x with him on mega man x. X is stronger than zero, if not right away then within the game.

Megaman X for the win. Zero may be a better character to play as, but Megaman is still my favourite. It is good to be the original, though Megaman X is no the original. Let me rephrase this... It is good to be close to the original. 

PS : Can you not use massive fonts to post, it is very annoying to read. Please just keep it to one font size and if you really wish to, make the title bigger. Just not any random big text!

In a fight between Zero and Megaman X and over the topic of who is better between Megaman X and Zero, id have to say Zero is better then Megaman especially X because of his superior dashing and jumping abilities and the fact that Zero did beat Megaman (copy X) before in the Megaman zero saga. Also I choose Zero because of his superior arsenal of weapons like the saber the b buster, the shield and the batons.

I'm going to compare Speed, Power, and Abilities to see who would win:

Speed: Zero
X and Zero have similar speeds, however, Zero has an air dash in most of the games

Power: Zero
Remember how Zero blew off Vile's Ride Armor's arm off?  Self-explanatory.

Abilities: X
X has been in more games than Zero, and has much more armors.  X wins this round and this round ONLY

Overall: Zero
X: 1 to Zero: 2

Sorry X, but the Saber wielder wins the fight.

Going with X for being the original blue buster  

Despite Megaman X's ability to adapt as the games go by, and as the Robot masters are defeated, Zero is just too good to be beaten by X. It shows in the beginning of the original Megaman X.

Well both X and Zero have their advantages and disadvantages.

X (Advantages)
- can attack from long distances with his buster cannon
- can acquire multiple armors
- can use Hadouken and Shoryuken
- can mimic every robot master he defeats
- he has more available upgrades

X (Disadvantages)
- his buster is nowhere near as strong as Zero's Z-Saber
- he takes more damage (generally) than Zero
- his buster takes a while to charge in order to make it more powerful
- he is not as strong as Zero

Zero (Advantages)
- has a more powerful weapon than Zero
- better at close combat fighting than X
- is stronger than X (when X isn't fully upgraded)
- is older and wiser than X

Zero (disadvantages)
- his buster is significantly weaker than X's
- is not suited for long range combat
- does not have as many upgrades as X
- charging his Z-Blade takes a while (I'm really referring to Mega Man X 3 here)

Both have their advantages and disadvantages (and I'm only naming a few basic ones), but if they were to fight, I'd have to give X the advantage.

Zero since he is adaptable in both close rage and long which makes him more balanced by comparison.

I swear some of you have never played the megaman X games, what X said at the very beginning meant nothing and zero acknowledged that because he hadn't realised his full potential like zero yet. At the end of the game you end up being the one to kill sigma. In X2 you defeat zero if you don't get all his parts from the x hunters. In x3 if you use zero against the little aircraft boss zero gets badly hurt and he gives you his saber. I can defiantly see Zero from the megaman zero series being stronger but then again we don't know how strong that X is because the only bit of his power we see is his body as a vault to keep the dark elf from awakening.