I have been thinking about the question that started this post, actually, because of my second knee and wondering whether to go ahead and get it replaced this year, or put it off as long as I can stand it.
Gringo...you answer your own question in Post #3 of this thread. You never know what the future holds for you or for the development of new technology. Best to get on with life and just think about the "now."
I experienced the same joy as you about going down hills and slopes. For the year that my knee was a mess, I had to go down even the slightest incline with tiny baby steps, worrying about falling the whole way. With the new knee, I just --- GO. It's wonderful, isn't it!! I'm so happy to hear you are doing this well.