I used a peequal at a festival, it was great, much better than the toilets which were horrific, and the queues were very short. Both were available so if you were doing anything other than a quick wee, you could just close your eyes, hold your breath and use the sawdust toilets.
The only problem was at one point I was using it and a man walked in (probably drunk, possibly a pervert) and stood up using the one next to me, which meant he could look into the cubicles either side. I wasn’t very happy about that and complained to security who went looking for him.
I think they are fair alternative at something like a festival where the standard toilet is already just awful. They were behind big barriers so not visible, same as the men’s urinals.