Balnibarbi
I like the tone of Gackpoid's voice, and he sounds awesome in Seppun wa Setsuna.
The thing is, I don't like Gackt very much. He's a very womanly man and that kind of turns me off.
But I do like Kaito's voice better. It has the cute factor.
Gackt's voice despite his looks, concentrates on Lows, so it is very wise if creator thinks about that as they make their songs.
Also to note kaito sounds like Makihara the famous pop singer in Japan during 90's who has wrote songs that sold millions.
Kaito is well rounded singer... u can tell from how he can cover many types of music.