Yes the current ones are all well and good, but a USB solution would be better.
Maybe, if you have a parallel printer and don't want to need a switchbox, and USB also provides enough power for a multitap. There's not much difference apart from that, except that psxport exists, USB adaptors don't (at the moment).
But the big problem in both cases is that 98% of Amiga programs bang the hardware when using joysticks so these solutions wont work anyway. Even PSXPort needs to run a patch on lowlevel.lib to work with progs that support it, if its psxport.device isn't used directly. All WHDLoad games and almost all older games can't use the psx joypad. :-(