I don't think we should blindly get on the gay/straight bipolar track with this new guy. It's totally plausible that he eats people and he's not sure which gender tastes better to him. Not that it'd be terrible if it turned out he was bi...like all the other people in this group probably are, but I would be happier if it was something else.

On Second Thought, Juugo being bi makes him most likely to be fighting against Sai.

I forsee the Team Kakashi vs Team Kakashi break down looking like this.

Naruto vs Sasuke: Obvious
I can think of noting in Naruto's current aresenal that can beat the Sharingan so he'll either learn something on the way or just have to Shounen Heart it.

Suigetsu vs Kakashi: You killed my master!
Mangekyou?!

Karin vs Sakura: I love Saskue the most!
I forsee Karin's special ability being genjutsu related, thus dredging up the long lost comment about Sakura being natural genjutsu user.

and finally Sai vs Juugo: I'm the gayest...no I'm the gayest!

These fights will all probably be fun, though predictable.