I haven't used the PS2 controller, so I can't speak 100% for it, but according to the documentation it seems to work for basic axis movement operations and zeroing.
The MPG you can move each axis with precision up to .0005" with the dial. It's pretty nice to have for using an edge finder/probe and it's similar to jogging you would get on an industrial machine. To my knowledge you can't zero any axes from it, however.
Just new to cnc myself and still building my plasma table and learning as I go.
As you might know from my post I am trying to fix my mpg, I think it was a power spike that caused the mishap.
But it gives great flexibility and precise movement like steelcogs mentioned.
At the moment I am using a Zoweetek Ultra slim wireless keyboard, Model: ZW-51012-1 and I find it good cause you can do all your keyboard commands and you are not tethered to the Masso, Pretty handy with a 3.1 meter long table. "Just something to think about"
But all said when I get the pendent going again I am thinking of a longer lead and will make me more than happy.
Only other thing, if you go for a pendent get one with an E-stop.