Bruised is definitely a highlight on an otherwise middling album. It Ain't Easy is enjoyable but I would demote it to b-side status.
Interesting the song left out of the writeup (Gotta Be You) is one of my all time least favorites from the ladies. Just utterly bland and uninspired, it makes Ugly/It Aint Easy sound fresh and interesting. Don't even get me started on the "this slut" line Amelle had to sing to replace the Mutya vocal. Of all the re-recorded tracks to include!!
I think they must have re-recorded it specifically so that Mutya's name wouldn't be in the lyrics on the reissued album.
There's a definite difference in quality between the songs the Sugababes co-wrote and the ones that they didn't. If you delete the ones they didn't write ("Ugly", "Gotta Be You", "It Ain't Easy" and "Obsession") the album is pretty much gold from start to finish.