Wing Chun is a bit different from all other martial arts, at least in my opinion. This is the reason for the extremely different reputations it has. I used to do it, and I could guarntee a win against over 80% of first degree black belts (Probably a more even) in any other style when I was one year into it with a yellow sash. When practiced correctly, with a good teacher and an almost excessive focus on sparring correctly you will be nearly unbeatable against all but the best practical fighters out there. As for multiple opponents, doesn't need it when you can drop most opponents in about 3 seconds, just go one at a time.
Now the problem with Wing Chun, as I found out reading web sites telling how bad it is. Most practicioners do not put forth the effort into it. Most people I've seen do it make a poor showing and would have never survived where I was. Most don't do sparring or reflex drills and are slow and have weak moves.
It is said that a specific style is not better then others in MA, but it is the practioncioner. This is an extreme degree in Wing Chun, and most that you will see are on the wrong side. Do your Wing Chun correctly, work on practical sparring drills and put more effort into it then anyone else you see and you will never doubt you are in the wrong style. You will know that those that bash your style know nothing about it.
If the site you are talking about is an MMA or BJJ site, to them anything other then MMA and BJJ is worthless. Not even worth the time to discuss it with them. Not a Wing Chun fued, its a any other MA vs them fued. Nothing wrong with MMA or BJJ, they focus on sparring to the exclusion of everthing else and are very effective against almost anything because of it.