I ordered two J-Sticks from Ultimarc to replace my Supers and threw in a T-stick + just in case I ever needed it or in case I really didn't like the J-sticks (not much info or opinion on them on the net). I was very satisfied w/ the Supers but I could not live without real 4 way gaming anymore.
I am very happy with the J-Sticks. The throw is a little longer then the T-Stick but they are very solid in 4 way and work well in 8 way. I highly recommend them...with two caveats.
One--if you do not have easy access to the bottom of the sticks to change them from 4 way to 8 way, get the T-sticks. If you do have easy access and want to save some money, J-sticks all the way.
Two--If you are a Robotron/Smash TV FANATIC (or Rescue for that matter, although I doubt there are many of those out there), and if you have played Robotron/Smash TV with a Super, prepare to be disappointed. I love all old 80's games but Robotron is #1 on my favorite list. The round plug and leaf spring design of the Super makes it absolutely perfect for the fluid movement needed for Robotron. I find myself getting stuck in the diagonals with the J-stick or T-stick.
Keep in mind that I don't have a problem with ANY other game--schmups, fighters, etc. all work great with the J or T-sticks. With Robotron, however, it seems to be very easy to have them slide up into the diagonal positions while you are in the heat of battle. Maybe it's my sloppy play and it might just be something that I need to get used to.