I'm not particularly a fan of Trixie, but she's a good character in the same way that all of the antagonists are well-developed. And I can see her dominatrix attitude as appealing.
I have to agree with everyone who said the mane 6 acted out of line by immediately attacking Trixie. We don't get to see what her act was supposed to be because it was interrupted by the others. Chances are, she wasn't planning on putting anyone down, she must be able to perform some impressive tricks to have gained recognition in the first place. But they don't give her a chance to prove herself. She does act conceited offstage, but when she does she is keeping up the reputation that caused ponies to have interest in her at all. I don't like that she was disrespectful to Twilight at the end, even though she and her friends disrespected Trixie's talent first.
I can't hate her for what she does. Ponies like to see her, Trixie is doing it for entertainment. Putting on a good show is her special talent. I find it odd that Applejack tells Twilight, "Your magic is a part of who you are, sugar cube, and we like who you are. We're proud to have such a powerful, talented unicorn as our friend." So, they'll accept Twilight's magic because she's a friend, but they won't accept Trixie for who she is?