"In-camera has the advantage of being able to be used with any lens, and the disadvantage of not being specific to any lens and so being a general solution that can't provide specific lens-tuned results (or as wide a range as lens-based)."
Can anybody explain me the disadvantage?

I...didn't quite understood what this fellow said on a forum...
Later edit: IS could work better with some lenses & to be less effective with others? Because I just remembered...when I tested the K10D with the kit lens I also tested it with an older FA 28-90mm lens...& lets just say the IS didn't performed that good.