This is a pretty old topic, however, I like to bring it back up. Ive been practicing Wing Chun for about 3 month now along with it I took a few classes of karate and boxing, even though Im not that serious of a practioner there are alot of differences in striking styles and concepts I like to bring up.

First the concept. Wing Chun is based on efficient fighting, using the smallest and fastest movement which genereate the most power in order to defend from attacks and attack your opponent. Alot of the Kung Fu usually seen are very flashy using big flashy movements easily dodged if fighting against a actual person. For instance in Aikido there are basic stuff, but when it gets into the more advance things it becomes really doubtful that you will actually be able to use it in combat. Wing Chun is different, all moves made are either to trap, disable, defend or attack your opponent in the simplest way possible, as Yip man said (the son of the master of wing chun) real kungfu is not flashy.

Second, the concepts are backed by physics and experiments. were they have tested the wing chun punch against the boxing regular punch. The boxing punch uses the shoulder muscle which is about 3 times weaker then the tricept. Along with the step in and momentum you get from the boxing punch it does generate more force, the thing is you can get probably 3-5 punches in with the wing chun punch of a good amount of force by the time you get a boxing punch. making the amount of power generated much higher. This is why in some mma leagues the wing chun punch is limited to 2 in a row. And if you research this you will see that most fighting experts would agree that the wing chun punch is the most effective hand to hand combat punch.

Third, fighting concepts. When teaching fighting in things like kickboxing and boxing they teach to back and analyse the situation. Wing chun is different, using training techinques such as sticking hands it teaches muscle memory, like when a basketball player shoots, he doesnt think about it he just shoots his body memorizes how to do it. This makes defending and attacking alot more effective. Of course sticking hands would not actually happen in real life but it does have practical uses when fighting, you just have to use the concept of it in a fight.

Wing chun is a fighting style that is direct and practical. It teaches a no nonsense way of taking down your opponent as quickly and efficiently as possible, no flashy kicks or takedown that you wouldnt actually use in real life. It teaches how to destroy your opponent as quickly as possible. The reason why it is not well represented in MMA leagues is because many practitioners complained that the rules disallowed many of the favorite wing chun techniques.

Wing Tsun vs. Street Fighter (Real Fight!) | Kung Fu Street Fighting | Kung Fu Fighting Video Blog

guy uses wing chun to take down a bigger stronger guy, real fight, in the streets, rare footage.

http://www.youtube.com/watch?v=i7gFbUc2-d8

human weapon video on wing chun

http://www.youtube.com/watch?v=RXg0FFREzcg

guy doing wing chun vs guy doing kickboxing

http://www.youtube.com/watch?v=VQTBArJYRVE

guy with good wing chun technique.

dismissing Wing Chun because it is a type of kung fu is stupid, it depends alot on the practitioner yes, but it is a effective combat system as well as a self defence system.