My school has one. As a first-year teacher, I was skeptical. My first quarter test scores were significantly lower than the other teachers', and I was incredibly humiliated (so were my students).
Instead of griping about it, I decided to make it something positive.
My students and I worked very hard last quarter to raise our scores, and when the results came in a few weeks ago, My students' scores were above the school's average! The data wall worked as a source of encouragement for my students and I. Our goal this year is to be the best of the best, and the data wall serves as a great motivational tool.
The school is just trying to keep us accountable for what we are doing each day in the classroom. I can't fault them for that. And if I'm not positive about the decision, I'll just be miserable and whiney.