Here is my overall rating of the JJ2 music:

Castle: 7.0
A solid track fits very well. Not my favourite tough.
Carrotus: 6.5
This one fits well to the set but I don't really like it.
Labrat: 6.2
I'm starting to hate the labrat music as I heard it so often. Fits well tough.
Colon: 6.7
Nice music, not great but it's decent.
Psych: 7.2
Crazy music I think. It fits to the tileset very well. And I like crazyness.
Beach: 6.7
Fits very well. Not my favourite track.
Sea: 8.0
I love this music track, it fits amazingly well and it's different from most other tracks from JJ2.
Diamondus: 6.0
I don't like this one. The original one was ages better.
TubeElectric: 7.0
This one fits to the tileset very well, but I miss a part of the original track which was my favourite.
Medivo: 7.0
This one doesn't have anything to do with the original. Doesn't mean it's bad. But it could've been a bit more near to the original.
Jungle: 6.7
Good music, but I listened to it way too often so I can't hear it anymore.
Ice: 7.0
Cool music. Sounds very frosty
Hell: 8.5
My favourite one. I just love it.
****: 6.2
Decent track, could've been better tough.
Boss: 6.7
Solid boss music, fits well.
Boss2: 6.5
Also fits well, but I think the first one is better.

Oh, forgot TSF:
Easter: 6.0
Very bad music
Sounds very happy.
Haunted House: 6.7
I like this one. It fits very well also (as the most of the JJ2 musics does).
Town: 7.0
Some time ago this one was my favourite. I don't like it as much as before now, but it's a solid track.

So, I think that's all. If I forgot something tell me please.