The real thing is better, however, since oftentimes bootlegs of video game and anime soundtracks actually sound worse, and the printing quality on the artwork isn't as good. Plus, they're freagin' bootlegs, so you should feel like a dirty sonovabitch for owning them. :o
I suggest buying soundtracks from Otaku.com from now on. Their shipping fees are up there, but they're fast, reliable, and totally legit. Seriously, if you're just going to buy piss-poor bootlegs, you might as well steal the music from a P2P or torrent and save yourself the money.
To be on topic... I borrowed a GBA Player once. It rocked my face. Kind of wish I had one. But then, I don't own a GameCube (my brother does), since I use my Wii now for GCN gaming, so it'd be worthless.
Oh well. I love my GBA SP+ anyway. LOVE that freagin' backlight (not sidelight like with the original SPs). Really looks gorgeous. Best way to display a GBA game, honest. Not even the DS Lite makes GBA games look as good, considering the games don't fill up the whole screen since they're of a lower resolution.