The surgery and recovery were difficult for me - harder than I'd anticipated. I worked very hard on my rehab as I firmly believe this is essential for things like this. Now that I've come out the other side, the new knee is much better than before. By now I expect it's about as good as it's going to get, though. It still aches some, and gets stiff after a bunch of walking or a round of golf, even riding in a golf cart. I make a point of icing it down after exercise to control the swelling. So I'd say it is only a little better than the other knee when the other knee's enjoying the full benefit of the shots. It's much better than the other knee when the other knee's shots have worn out. I'm sure they'd both feel somewhat better if I'd drop some weight.
As long as the shots continue to work, I'll probably continue that way with my other knee, as I'm not in a hurry to put myself through the surgery ordeal again. But my doctor has been somewhat surprised that the shots have lasted as long as they have for me. He says typically each series works for a shorter period than the previous one. So it's just a matter of time before I'll have to get the other one replaced, I suspect.
We live in a community that is primarily retirees, so there are lots of people around here with artificial knees. Everybody's outcome is different. Some are truly wonderful and they couldn't be happier. Some are still in pain and don't think the replacement is all that much better than their original arthritic knees. If you just knew where you would come out on that scale it would make your decision a lot easier - but of course you can't.