I had to switch to the JB Fab twin sticks when I installed the Advance Adapters NV3550 kit.
I had no problem at all with my old "J" shifter. It would shift on the fly "like butter." I guess I was one of the lucky ones that still had the boot sealing the shifter mechanism.
As a matter of fact, my girl found it easier to use than the new twin stick setup. With the twin sticks she isn't sure she has it shifted into 2 HI, Neutral, or 4 hi. I've got to admit, there is some guessing as to what position it's in. You were sure with the old "J" shift.
Sure the twin sticks work great, but if I wouldn't have had to change, I would have been happy with the old shifter.