My main beef with these joysticks is that you can get pretty much any of the games on Namco Musuem volumes. For example, if you track down Namco Museum vol. 2, for the PS1, you get Super Pac-Man, plus Gaplus, which is a fantasic sequel to Galaga. Sure, it's more expensive, but the emulation is great.
Now, if you're talking about the plug and play controllers that have games like Slap-Fight on them, that aren't on any console collection, (or are insanely expensive) that's another matter. But I don't even know if anyone on here has purchased one of those controllers, so I cannot say how good the emulation is. (See this thread:
http://shmups.system11.org/viewtopic.ph ... slap+fight)