I was very happy to have "worked" with Zeljka Kojic in the contest for a book cover for "Creating the Knowledge Network WOK".
During a contest, you don't actually "work" together but in practical terms you actually do. She understood the concept and came up with great stuff quickly on her own and then responded very well to my suggestions for improvement. To do a good design you need to bounce your own ideas against a great designer that can respond to your needs and understand the goal.
I felt she did this very well and I hope I will work with her again in the future for upcoming projects.
So based on my experience: I truly recommend her.