Glucosamine Chondroitin

My wife was diagnosed a couple of years ago with arthritis in her knee, and along with that the cartilage in the knee is damaged and wearing thin. She takes Voltaren as prescribed by her orthopedic specialist for the pain, and it does help. I recently seen a commercial on tv for a product called Osteo-Biflex. It claims to help the joints including the tissue and cartilage. I asked the doctor and he said as long as she wasn't allergic to any of the ingredients in the product, she could try it. I saw it in our local warehouse club, and also found a generic alternative, (Glucosamine Chondroitin Complex- identical to Osteo-Biflex.) This alternative was $10 less in price. What I am wondering is if anybody has any experience with this type of product, or something similar to it, and if it helped them. The instructions say you have to take the product over a period of time to realize the benefits, and I was wondering if you have taken it, how long before you noticed any benefit, if any. It's a pricey product, but if it works, it's worth it.

I use Glucosamine Chondroitin, I do notice a difference whether or not its the actual pill or some other change I have made. Here are some links I found....
http://www.arthritis.org/conditions/alttherapies/Glucosamine.asp
http://orthoinfo.aaos.org/fact/thr_report.cfm?Thread_ID=219&topcategory=Knee
http://www.quackwatch.org/01QuackeryRelatedTopics/DSH/glucosamine.html

My parents take it every day and they love the stuff and say they noticed a pretty big difference (they don't have to take pain killers anymore).