Brax,
I just went to the laundromat next door that has an old ms pacman machine in it. I felt the joystick compared to ultimarc's j-stick, and here's my review.
The j-stick, when mounted in 3/4 MDF sits at almost the exact height as the original ms pac stick (it's tough to measure to the top of a rounded surface). Let's put it this way, if there is a difference, it's not noticeable in looks or feel.
As far as the action is concerned, you can definitely feel the restrictor on the bottom of the j-stick. If you move the j-stick, you will feel the "corners" (not really corners because it's a 4-way joystick, but you feel corners at the cardinal directions--up, down,left, and right). Part of this has to do with the fact that the j-stick does not have as much tension in it as a real pac joystick (weaker spring?). I also noticed that the real pac joystick felt "spongey." When i pushed the joystick up, resistence on the stick became tighter and tighter. The j-stick does not experience this "spongey" action. You could move the entire range of motion without feeling too much resistence on the stick. In other words, it's a very light handed joystick, that would be ideal for quick movements.
As far as playability, I think the j-stick is great. As I said earlier, I'm able to slide from one cardinal direction to the other without feeling a kink or wave like some of the restrictor plates LOOK (i say this b/c i haven't used a plate) like they may cause. All the 4 way games played great with the j-stick and i would highly recommend it!!. As far as I can tell, the tension in the stick is the only difference between the j-stick and the real deal.
I'd like to hear from some others who have tried the j-stick.
wee beastie