Fushigi Yuugi is one of my all-time favorite anime series. (Actually, I'm a really big fan of Yuu Watase's works). And guess what? I have no problem with Miaka. In fact, Miaka is my favorite character.
For most people, it seems, Miaka is too whiny for them to handle, and promptly stop watching the series, because she is too annoying. But it doesn't bother me in most cases. In fact, I am typically the fangirl of that whiny character. Sailor Moon anyone? Usagi's my favorite character in that as well. I'd rather watch a series with a main character like Miaka, rather than one like Haruhi Suzumiya (no offense to all the Haruhi fans out there - I will admit that I didn't see the whole series).
But as I said in my last post, different strokes for different folks. So people out there, don't just go, "I HATE MIAKA!!one." Please have an intelligent debate over her character flaws, and realize that some people actually like her, and that they feel that their opinion is not being respected. But also, we must respect the people that don't like her as well, and don't go around going, "OMG, how can you not like her?!eleven". Remember that it goes both ways.