I like Hikaru. Shes my fav J-Pop singer..... buts thats probs coz the only other person I've heard is Yuna Ito. I have all her albums even the English one she released in the UK and US..... I dont really like that one as much as her Japanese work. I admit shes not the best singer out there.... especially live performances, but I like her style of music. Did you know she wrote and recorded her first song when she was 12? Thats pretty good.
I prefer Simple and Clean to Passion/Sanctuary. I dunno why. Its probably the remix that did it for me lol.