This topic has been covered a few times, but seeing as you're new, I'll copy and paste my thoughts on it (which I had written some time ago):
"Anyway, a bit about myself first: I won't say I'm a Wing Chun pro, but I do have experience with it. I've trained with Chris Chan, an live-in student to Ip Man and sihing to Bruce Lee, and I've discussed technique with and also sparred a number of Wing Chun practitioners before (including practioners from Hong Kong and China, with whom I have no communication gap as I speak Chinese as well ). My Muay Thai training started in 2003 with a certain formerly large camp that also happens to manufacture equipment and promote fights at Lumpinee, and my primary trainer was a two-time Lumpinee champ and one-time Rajadamnern champ with ~350 pro fights under said camp's banner. I don't have any meaningful competition experience, but I have been to the old Lumpinee Stadium, visited Petchyindee Academy, and have contacts at Saengmorakot and FA Group gyms. In terms of striking, I also have experience cross-training with Kyokushin Kaikan, Enshin Kaikan, and World Oyama Karate (all full contact karate schools), Chen-style Tai Chi (and a bit of Yang style too), Queensbury rules boxing, and a touch of Choy Li Fut.
From my experiences, I have the strong opinion that Wing Chun is a fundamentally flawed system. It's designed to be effective in only a very niche range, namely the range between clinching and what typical stand-up fighters consider a typical striking range. All the fancy blocks and parries in the "sticky hands" range are neutralized by several things: 1.) good, strong straight attacks inside "the pocket" like jabs, crosses, knees, teeps/front kicks, etc., 2.) powerful long range strikes outside of their effective range like round house kicks, front kicks/teeps, or Thai-style "long knees", 3.) lateral/circling movement like tai sabaki that flow into round house kicks or crisp hooks, 4.) a strong clinch game with knee and elbow strikes, 5.) takedowns, either from shooting or clinching. Wing Chun's over-reliance on perfect parrying and trapping to the detriment of practicing simple and effective blocking is a danger to themselves, and the linear nature of the style's footwork further magnifies its flaws in ranging.
Furthermore, Wing Chun professes to develop good internal power, but the insistence of the majority of practitioners to refuse to pivot their bodies into strikes (that is, commit to them) causes a failure to generate enough power to cause knockdown or knockout. Reliance on dan tian alone without proper body mechanics amounts to martial mythology in my opinion, unlike the combination of dan tian use with proper physiological movement as seen in karate and especially Tai Chi (particularly the fa jing of Chen-style Tai Chi). Even in Muay Thai, Thai trainers will encourage you shout and tighten your abs while using hip movement to generate force with all strikes. Wing Chun's reliance on chain punching is more a nuisance than a threat, and fighters who are trained to receive any sort of hard impact are unlikely to be phased. Not to mention that a stiff jab or 1-2 will neutralize any hope of chain punching finding its mark, and even a decent shell guard will prevent you from being overrun. With both their offense and their defense neutralized, what often happens is that Wing Chun practitioners can be overpowered and overrun by nak muay, kickboxers, knockdown karateka, and other full contact standup fighters. Even if Wing Chun were to be practiced with hard, non-compliant sparring, like I said before, their body mechanics, especially when combined with their footwork and ranging, are fundamentally flawed and the only possible evolution I could see happening would essentially depart from Wing Chun's very foundation (see: Jeet Kune Do).
In conclusion, it is my opinion that Wing Chun talks a strong game but is only effective against those with no martial arts experience. I would say that it would not even be effective against a tough barroom brawler a la David "Tank" Abbott. What gives Wing Chun its mystique is its long history and the ability of its long-time practitioners to sell themselves through a combination of tall tales, parlor tricks, and opportunism. The verdict: Wing Chun may give you a split second to run away from a fight, and sometimes that's enough. For anything more, seek another style. The only other benefit I can see in Wing Chun is that it can be used as an effective form of cardiovascular exercise that anyone can do regardless of age or shape."
