Well, this is reli subjective because, from her "best works" like I am..., which happens to be one of my least favorite albums from her anyway, are also "bad" songs that don't appeal to anyone at all.
If you ask me, I think she probably made a mistake with Secret & GUILTY. Probably she shouldn't have rushed Secret into a full album; it was decent, but something felt lacking in the album, you know what I mean? Or rather, it's that feeling that because she rushed it, the songs could've been better or something.
As for GUILTY, I don't know if it's her or avex, but I think whoever who decided that she decided needed to release GUILTY at that time needed to be shot. She was obviously in the worst of her moods & times, and for her to record an album? She even confessed to hurriedly writing lyrics to a few of the album tracks just to complete the recording... I do agree GUILTY was a dark & raw album, however, there was also that feeling of, "Get it over & done with" with GUILTY, ya?
NEXT LEVEL was just another oddity too; it felt like she was THAT desperate for something "new, a "change" that she just jumped into what the current trend was without considering if she actually fit it. And that's how we got the PV for Sparkle.
With Rock'n'Roll Circus, I think she's back again. Or rather, she has cleared her mess from Secret and is ready to rock again.
MOON/blossom was unimpressive though, just sayin' ^^
But of course, she had gems from the Secret era onwards; JEWEL, BLUE BIRD, Together When... Days, these were the real good songs I felt from that 2006-2009 period
