I tried to see the show standby Thursday evening. I arrived at the standby line area about 6:30, which was clearly later than optimal. A CM was saying that only standing room remained, so I had notice of what to expect, but I waited in the line for at least 30 minutes, then was led to a standing area room above the Asia side seats shortly before the show began. I may have been a little unlucky with the specific position I got, as there were quite a few people standing one level down from me, which somewhat obstructed my view of the foreground. I had seen the show from the fastpass seats once before, and the view from the seats is considerably better, both from being closer and without any obstructions. My impression, although this might not be correct, was that everyone in the standby line eventually got into the standing room area, so that I might have done about as well by arriving in the standby line quite a bit later than I did.
I like Rivers of Light quite a bit, but don't really view my standby experience as successful. It was a long wait standing in a stationary line outside the theatre, leading to a less than fully satisfying view of the show. On the positive side, I was one of the first people out of the theatre at the end of the show, and was able to leave the area without much congestion.
I think that if you need to do standby and want a good quality experience, you should arrive quite a bit earlier than I did. Of course, that will require a long wait, but perhaps you can wait while in your seats.
Hopefully fastpasses will be more easily available as time goes on, when the show is offered every night, and when Pandora opens.
