I'm listening to the song right now and this is probably the first song of hers that I can't come up with an immediate opinion for. I don't think this song is made out of gold like it seems many here do.

But I've always liked techno, though I prefer the type of techno that she did on love appears. I think this song will take me multiple listens to really get into. So, so far I much prefer Rule, but Sparkle might be a fun club song to dance too (though I think I would tire of it after the first few times.)
My only immediate thought upon hearing this was that it sounds like something Madonna or Britney Spears would put out today. I'm not sure whether that is a good or bad thing really.
I also do like the fact that this song is a pretty new style for her - so at least she is trying some new things. Geeze! I am so conflicted about this song aren't I?!
As for the lyrics, I actually agree with Maikeru. I don't think that Ayu's lyrics need to be deep and meaningful all the time, but I do think that good lyrics are important since they are one of the main things that got me into liking Ayu in the first place. Sure, Koda's lyrics are more explicit, but I can definitely see where these lyrics are "koda like." My grasp of Japanese is far from perfect, but even I can tell that she is speaking in a very slangy and kind of "dirty" way here and that is just something that fans are not used to from her at all. It doesn't mean that it is wrong, I just personally think that style doesn't suit Ayu. So while Ayu may not be saying something bad explicitly, its kind of in the way she says it. Much like Koda's radio comment about women over the age of 35 having bad amniotic fluid - what she said is actually technically correct, but for the Japanese, the WAY that she said it was very offensive since there are so many positive or negative nuances in the Japanese language.
And I really hate the "sexual lyrics just show her maturity and the fact that she has become a full grown women now" argument because to me, those kind of lyrics are usually more about immaturity than anything else.
Maikeru: See, its possible for us to agree on something!