honestly, every anime that adapts a music manga has clearly an advantage, namely that you actually can hear the music
Iiiii dont' know, for me I usually don't like it, I think it's more inherently a problem for the anime to adapt a musically oriented series.
BECK was one of my least favorite musically oriented animes because I thought it had a big hurdle going in: making some teenage rock band actually sound like the cunning and talented musicians the manga portrayed them as. While the manga was very expertly "fill in the blanks" with what it provided, it did give us enough information that BECK sounded something like (I'm working off seven year old memories here I might be wrong) a Japanese, pop-aggressive Red Hot Chili Peppers-ish group. I think the way he drew them made them seem more hip and loud too. So we've got a good vague idea of their sound.
But then in the anime BECK (again from what I remember) was like three different bands entirely and they sounded pretty much like any other Japanese rock group that plays at live houses. I didn't really ever get the illusion they were actually that worthwhile and I think giving them a genuine voice just kind of ruins the illusion of the manga. I couldn't buy for a minute that the crowd at the music festival could seriously get into them that much and when the manga made such a big deal about the band being a big player by the end of it, it eventually gets kind of comical as I wonder "why are they famous" whereas in the manga I totally bought into it.
I GAWT A FEE-REN!! was basically where I just ended up laughing instead of feeling that life affirming enthusiasm the manga gave me. But uhhh they gave it a shot? I don't know if most studios give a fuck about actually hiring super talented guys to put in the effort it would take to convey a unique sound for BECK and Madhouse isn't exactly a big budget studio. So I get why BECK is the way it is.
Oh i just remembered. And there's this great moment in BECK when they see their rival band perform and the lead singer is this muscular, short-haired guy in his underwear screaming on stage, with the guitarist being described as a primal power of chaos. The lack of music in a comic book and the power of the imagery displayed means so much more than what some anime adaptation could try. If it ever got that far in the anime I kind of figured they'd sound like a generic black metal outfit, when they seemed so much crazier and ~avant~ to BECK's pop. And hnngh A+ comic book.
On the PLUS side of anime music series adaptations though..!
Sakamichi no Apollon, though I hate what the story turns into (after around episode 5 or so, around the time it stops featuring jazz prominently), was one of the exceptions because it actually genuinely sounded perfectly in synch with the visuals; very organic and natural. It never sounded like pre-recorded stuff, it always felt like the characters in the show were really PLAYING it!
Legend of Black Heaven is also good from what I remember, though not for those reasons obviously since it's even older and lower budget, and Detroit Metal City is a good example of just GENUINELY sounding fucking spot on for what the band should sound like. It being comedy-oriented helps, but it's legitimately good music (kind of parallel to Metalocalypse also having good music). I listened to Fuckingham Palace like ten times in a row when I first saw that episode.
I know there's more but I can't think of any, haha.
I haven't seen Nodame Cantabile so I can't say how that sounds, but I do love the manga