the problem with wing chun is that the quality varies widely among schools - wing chun ist not a trademark, so basically everyone can open a school and call himself a wing chun master.
I've trained wing chun for several years, and I can assure you that it's a highly effective and aggressive style (we often sparred with people from other styles) - but as stated above, it all depends on the trainer and lineage - there are major differences between the interpretations of Yip Chun, Yip Ching, Duncan Leung, Wong Shun Leung, Wang Kiu, Leung Ting etc. (all of them students of the last "grandmaster" Yip Man).
Personally I can recommend the Wong Shun Leung lineage (note that Wong died some time ago, so his students are now in charge; the best-known in Europe probably being Philipp Bayer and Barry Lee). Wong's stye is straightforward, and puts an emphasis on sparring or gor sau, and in general, real-life applications.
If you give me information about the school you're considering (webpage?), I can tell you what kind of place it probably is.
In reference to the bullshido.org link, I would like to comment an two statements there:
"Because many of the hand techniques involve eye jabs, and bare hand strikes, most Wing Chun schools do not spar full contact."
This is rubbish. There is a single eye jab technique in the entire wing chun system, and this is in the "emergency" form (biu tze), and noone would use it in sparring. the wing chun straight punch is the main weapon of the style, and that's what you also mainly use in sparring. "open hand strikes" are what you would typically use if you don't want to hurt your sparring partner (i.e. slap instead of punch).
"Students spend a lot of time on the chi sao exercise to “improve sensitivity”. While being able to feel what your opponent is doing by touch is a useful skill, the average person who attacks you will not be holding his hands like a Wing Chun student, so most of this skill is not applicable to real life."
chi sau is a reflex training for in-fighting, nothing more. it helps you develop the skills to adapt to different close combat situations very quickly, and trap and immobilize your opponents hands/arms with one hand so you can hit him with the other. it also helps you to kind of "automatically" follow your oppenent when he trying to retreat (hence the term "sticky hands" ) - you simply don't let him get away, but stick to him until you've had a chance to strike. and all this has nothing to do with the way your opponent is holding his hand.
I hope this helps a bit.