I used her before her range on her Q got nerfed and after.
I think Orianna is a really good harasser mid lane, with her range from the ball (Which has been nerfed, sadly enough) she can easily farm and harass the oppent. The funny thing is Orianna's auto-attack stacks in damage, so it's kinda funny to see people buy Malady or Wit's End to her, to make her auto-attacks stronger, which i haven't tried yet. ^^
But if anyone wants to try some new champion with a bit of a learning session to learn how to the champion works, Orianna is definitely the best option you can have!