If you have knee or ankle issues, then I see no problem with the jointed irons. But my personal opinoin, if you are Eventing or doing Jumping, that you are better off with the ol' Fillis Irons.
The jointed irons, have been known to fall apart during a ride, and riders have ended up in accidents because their iron breaks during the middle of their ride.
George Morris wrote an article on them because they became quite the fad in the Hunter Ring - and he wrote an article against them because of this fault in their design.
Not much longer after reading this article, I was at an Event when there was a rider who ended up in this predicament because her jointed iron broke during her CC run.
For that reason, I wont, I refuse, to own jointed irons.
I have no knee or ankle issues, and I refuse to buy an iron that is a fad with riders. I don't follow trends or fads - and I am glad to know that I am safe and secure in my irons.