For photographers, this is an absolute treat with hundreds of candles, illuminating the landscape against the massive columns of the Treasury. If you want photos unobstructed by people, try to line up early before Petra opens again in the evening, then sit in the front row right before the lanterns. The ceremony itself is traditional music and stories of the site (dress warmly since the desert is rather cold at night and bring a flashlight for the walk to the treasury). In my opinion, the views and photo opportunities are better than the show itself.