Both are
amazing albums, perfect in every way. It's such a hard choice but I have to go with Party Queen. It is just something experimental and exciting for Ayu and it has songs from various genres; all of which are impressive. JAPONESQUE feels like a logical progression from her previous works- it's new for Kuu but not surprising given the direction her music has been taking the past few years. All in all, I love them both.
I listen to them both all the time.