Interesting question. I think everyone will expect me to answer Ai, but that's not true. I like her a lot, that much is true, but like writing her? Oh no, she's tough. You really got to put yourself out there in order to write her in the way I think she's like, and it makes me feel really drained emoting like her. Lol.
So, my favorite character to write is, oddly, Sayu.
The narcissism, the cute side, the evil side, the completely-hopeless-at-athletics side...all of it. She's just really fun and amusing the moment she appears in any story.
Which is why I have lots of fun with her.
Reina gets an honorable mention because I like writing her into situations that make her a sulky kitten.
I'm evil like that. Hohohoho. :3
Can't really tell what I like to read though, since what I appreciate is the writer's skill at portraying any one character, specific to the situation they're put in. It's hard to see
good portrayals of the characters in most cases, so I often just read it for the fun situations. But I definitely like OTN1's Miki a lot, it makes me feel like I'm seeing the real Miki at work. That's the kind of thing I look for. So nope, I don't really have a favorite character to read about. Except possibly Ai, because I like her best, but then again it depends on how she's written and all...