Panel de Pon in general is an awesome puzzle game. Pokemon Puzzle League is an even worse conversion than Tetris Attack was, and Tetris Attack wasn't even a bad reskin at all (especially considering it was done in Japan, anyway). Lemme explain.
PPL is, according to what I heard, the result of a bunch of DigiPen students taking the unreleased Panel de Pon 64 and making it into something NoA could then capitalize on with the whole Pokemon craze that was going on back then. The result definitely feels amatuerish in aesthetics, but the gameplay is actually the best of all versions of Panel de Pon/Puzzle League.
With that, Pokemon Puzzle League gets a lot of things right if you're looking for the ultimate PDP experience, and it's fun all the time no matter who's face is on it (until there isn't a face on it, like recent games...). Plus, you gotta love the campy lines from Team Rocket. And hey, Nidoran's in it, so I can't complain. I sold it off once before when I got over my obsession with all things Pokemon years back, but bought it again real cheap during the Gamecube era because I realized it was still solid PdP outing despite being aesthetically lazy. That, and I wanted to have an easily accessible Pokemon voice soundbank on hand. Nidoran's voice is so cute. :3
I actually liked Pokemon Puzzle Challenge more, it felt less... dirty. It had the soul PPL was clearly missing. It was made in Japan, and you can tell as it starts to become more lively like Panel de Pon (SFC and GC) and Tetris Attack. Plus it had Chikorita, Sentret and Totodile, and maybe some other favorites I've forgotten. It's no longer the best portable version of PdP, but probably the last visually interesting one.
Finally, the only thing that PPL lacks outside of class is a four player mode, which PdP GC does have. You'd have to import it (and now it'd be almost impossible to find), but it's almost hard to go back to playing any other version after that. PPL maybe be more polished mechanics wise, but PDP GC beats it by being the best one aesthetically (though some music isn't as good as the original), and having that four player mode. It's otherwise identical to PPL but like a 1.0 release, while PPL is like the 1.3 release of the same game.
Oh, and Panel de Pon for the GC is the unreleased 64 game that turned in Pokemon Puzzle League, FYI.