I'm another KuroFai fan. :p I think their personalities and strengths/weaknesses compliment each other surprisingly well. And despite how it may seem initially, I don't see any real animosity between them. Fai loves to tease Kurogane and Kurogane eventually gets used to it. ^^; I read a comment by someone on another website that said there is a rivalry between them... which I completely don't see. It doesn't seem to me that they ever try to compete or get ahead of one another... really, I think their strengths and weaknesses are just too different for them to react that way torwards each other. Although, back to Fai's teasing... for some reason, many times, it seems like Fai is subtly flirting with Kurogane by teasing him. I can't remember exactly what they were at the moment, but I remember a few comments Fai made torward Kurogane made me raise an eyebrow, and I looked at my roommate (who I watch most of my anime with, lately) just to see if she seemed to react the same way, and she had the same expression on her face.
; But maybe we're just reading too much into it. (Even if we are, though, it's still fun.)
Kurogane and Tomoyo together just seems so... wrong. No offense to those who support that pairing, but for me, there's just too much of an age difference between them. I'm not certain of their exact ages, but Tomoyo looks like she's still a kid, and Kurogane looks... much older. It would seem a little like pedophelia to me. I'm not always against a relationship between an adult and a teen in fictional relationships, but this one just isn't working for me. Nevertheless, I do love both characters. Particularly Tomoyo, since she was one of my favourite characters from Cardcaptor Sakura.