Of those choices listed, I'd have to go with Nail Geek's system. I prefer any type of articles be searchable by the user when they're using the vB search functions so by using a forum to drive the articles solves that problem nicely.
Both Geeks and cinq's systems offer a lot of features and should do the job for most people but my deciding factor went with the searchability of the articles in Geek's method.
Note: If you're vBa CMPS user there is also another option available for you.... the CMPS Articles Module by Tom M (not sure if he gave it actual name or not

). It's a pretty basic system but if somebody is using CMPS and needs a quick & dirty articles system that is also based upon the forums then it's worth looking into.