Unique isn't a description of an opinion, really. Did you like him? Did you not? What did you think of his notable personality traits? What of his story, his development, his style?

I could say Seymour and Red XIII are both unique characters, but that doesn't tell you what I think about them, that just tells you that they are not the same as other characters. I detest Seymour as a character and I love Red XIII.

As for me, I liked and disliked Squall for various reasons. I disliked his mopey emo attitude at first, particularly his anti-social behaviour... but I liked him in the long run and even grew to like those parts of him after getting a better understanding of why he was that way. Him not opening up at the start to anyone also meant that when he did open up to people, it was a more notable development.