I think the Sugababes are - or were - pretty amazing. The two post Mutya songs were bad but the heights they've hit previously have been pretty fucking high.
Here is something I recently wrote about the gorgeous "Ace Reject", which wasn't even a single:
Sugababes - "Ace Reject"
This song has become immensely important to me over the last year or so, for reasons i can't necessarily pin down.
One of the things that makes (made?) the Sugababes well-equipped to do big, epic, lifechanging pop ballads is the really clear differentiation of their voices, which comes through very strongly in this tune. In fact apart from the chorus, the three girls sing entirely different melodic lines - Mutya does this kind of depressive, resigned verse/bridge, and as it so often does her refusal to adorn her vocals comes across as a kind of wisdom, she sounds so much older than she is, like this is the final chapter in not just a love song but some epic in which two lovers are kept apart not by fate but by their own choices, their own betrayals. Then Keisha swoops in with an entirely different verse/bridge that is much higher and almost cathartically frustrated, and yet very pure - Keisha always sounds cosmically right in such songs, like she's the voice of the relationship as well as a voice in the relationship.
Heidi gets a bit shortchanged on the middle-eight, partly because it's such a typical place for her, and partly because she sorta sounds distant and multitracked, subsumed within the song's expression of fragility rather than offering her own stamp on it. But it's a great middle-eight, so camp in its melodrama, which really of the three only Heidi can pull off - that quiver she puts into it is perfect. Heidi's vocals in these songs always give me a "slowly rotting away in a decadent but lifeless celebrity relationship" kinda vibe, I imagine her in a white dress in a white room eating a plate of spaghetti with pesto, all alone (also she gets the great first verse in the next song "2 Hearts").
Underneath it all the slightly ska groove pretty much does not change at all, just accumulating airy synth and guitar layers like a stick accumulating fairy floss. The chorus is as pop as anything the group ever did, and it works really well, its overt repetition matching perfectly the repetition in the lyrics ("We break up to make it up/back and forth we never stop/every time a change of heart/can't keep up"). The formula of the chorus might not work if the verses (particularly the first) were more straightforwardly complicit with it, but instead the song works on a split level in a reverse of what you would expect: the verses are outside the drama of the relationship looking in, effectively an expression of the intervention, whereas the chorus is the relationship itself, unchecked and uncheckable, all the reflection of the verses lost.
The song is a depiction of a relationship at the breaking point, but when I'm not focusing on it, but simply listening, the story of this song is not about an actually existing relationship but a relationship-to-come, a complicated love letter to someone the singers haven't met. It makes me sad because I wonder, somewhat incoherently, if this is the best they can hope for.