IMO Glucosamine is one of the few supplements that I can truely say really work. It took almost two months @ a gram a day before I really noticed anything in the way of pain relief; and now I wouldn't think of giving it up. IMO great stuff.
I wouldn't let a bad review stop you from taking it. I use it. I live with fibromyalgia, a chronic pain/arthritic disorder, and cannot be without it in the winter. I also use it on my old arthritic horse. Horses can't lie about results! I will add that I prefer to use it with MSM and chondroitin sulfate.
Word of advice, if you have knee problems, don't try to take up snowboarding Anyway, I've skied for 20 years and decided to try snowboarding.... long story short, my knees hurt so bad for 2 months I was about to go to the doc but it was tax season and time was short so I started taking Optimum JSF (thanks to Gopro's recommendation).