Megurine Luka sounds awful in every song I've done.
It's even worst in her room.
I actually really like Luka's voice...in some songs. I don't think the selection of Luka songs in F is that great, though. There were some good ones in earlier games (like Double Lariat, which is actually the song I blame for me getting into Vocaloid music in the first place...).
They need more stuff like this
. Or this
. Or more recently, this
Ha! I actually don't mind Miku OR the Kagamine Twins OR Luka.
Meiko is just awful, though. Go figure.
Well, you have to understand that Meiko is old
. In fact, she's the first Vocaloid Crypton ever made. She's built on the original Vocaloid 1 engine, along with Kaito. The rest are using Vocaloid 2, which was a pretty major improvement.
But anyway, the best Vocaloid isn't any of these. It's IA ;)