I went this morning and it was an amazing experience, even better than the grand opening of Hogsmeade. Walking through the wall to Diagon and seeing all the staff, the confetti, and the red carpet was thrilling. I was nearly in tears as we headed to Gringotts. It was very overwhelming. The line for Gringotts when it opened was basically an unorganized cluster outside the building, so my group ended up in pretty good shape. Our wait time was maybe an hour. And wow. That queue. Breathtaking. I have so much more I could say, but I have been up for nearly 48 hours, and have been at Universal since 3:45 (we had to camp out in a McDonald's parking lot because they turned us away until 5AM).