Alright after playing with both fighters with equal amount of time, I've concluded Kung Lao is better. Before all of you Liu fans kill me let me explain.
Playability goes to: Kung Lao
For some reason I feel good or better preforming his combos, and they seem easier. Hell I killed Goro and Kintoro/Shao Khan with Kung's air combos alone... I had to run and shoot my projectiles with Liu.
Projectile: Liu Kang
This is very easy to see his projectiles are faster, and easier to use, which led me to using physical attacks/combos on all of the bosses.
Combo King: Kung Lao
During the begining alone *the first three oni in the game*, I racked up 120 hit combo on them with his air quick attack combo. Which also got me Toasty rating, and enough experiance to upgrade to level 2 on most of my skills. *The Oni King/War Lord in the Pit area racked me up to 150 hits, which led to flawless spector.
Now this may differ for some of us but I give it to Kung. His running speed attack is not only useful for escaping projectile attacks, but also is an easy way to kill Goro, etc.
Better moves: Liu
Simply put he has better moves, Kung Lao's Spinning attack is great if used wisely, and his hat has saved me but Liu is just more powerful in that department.
Boss Killer: *the harder ones near the end* Kung
I killed Ermac within 20 seconds. *Ok so 23 seconds*
Goro never even hit me before I combo'd him into oblivion, and the rest died pretty quicly with the exception of Khan who thought he would kill me with his stupid spinning hammer luckily I kicked his feet out from under him. *The speed attack while running works wonders*
This is highly based off of opinion. I mean I love dragons but Kung Lao's rabbit fatalities, and buzzsaw fatality. So I conclude a tie.
Death wise: Both seem to die in huge swarms after LONG periods of time.
Speed to beat game: Kung
Liu: "1:53" 1 hour 53 minutes.
Kung Lao: "1:22" 1 hour an 22 minutes. And yes I did KL's story first so I knew my way through the game, and skipped Smoke's missions in Liu's story./Ermac fight.
Highest jump: Kung
During the begining stage I easily got that one red yin-yang item in the second room at the top of the cieling just by Kung's air combo.
I noticed even Liu's shorter combos are a tad bit stronger than Kung's combos.
Also this topic was to explain an easier means to kill Goro, Kintoro, Shang, and Khan.
All you have to do is A) Start running
b)Shoot projectile of character
C/D) If they stumble back combo them with an air attack *only use air*, if they don't run at them and press the quick attack button/speed attack button. You should ht them for about 3-4 hits, and do more damage.
E)Repeat and they should go down in NO time at all.
Unlike most people who say use projectiles and then run. Wrong. Run, shoot, combo/speed attack, repeat. As simple as that and it takes WAY less time.
Now I just have to play through Scorpion's/Sub-Zero's story to find out who is better there.
Another thing, I noticed many people complaining about the sound for the MK2 unlockable... Maybe I'm lucky but mine sounds the same as my SNES version/SG version with the exception that Barak's projectile, and "Fatality" don't sound quite right, and I get music from the stages exactly like from my MK2 cartridge...
*Although still haven't been able to fight Smoke damn you Midway!*
I guess that is it for now. I'm sorry if most of this has been mentioned before.