I like both. Even though Xion was just a replica much like Repliku, she seemed like a good character. She had some purpose, and it makes the Riku/Roxas fight more understandable.
As for the Organization, my feelings don't really change. I probably feel some sympathy towards some of the members. Seriously, some pf the members were left completely left out of the dark about Xion until things got out of hand. It seems pretty messed up, but it's not like they need to be an organized organization.