I played it for the first time since 2007 about 5 or 6 months ago, and if I'm being honest, it didn't age well at all. Every character, even the light characters, feel like they fall like a sack of bricks. It also doesn't feel very satisfying hitting a strong attack like in the later games. Speaking of getting hit, it feels like you can't really DI away from the blast zone and you just die. Easily the second worst Smash game after 64.
That said, I still have very fond memories of playing it with my ex-best friend, and playing as Young Link is what got me into wanting to play Legend of Zelda. Other than that, I feel like there's no reason to go back and play it. Especially with Ultimate just playing better.