It seems to be the preferred, cheap and quick method of getting a second row of choristers on a different level in a whole variety of tight and unconventional venues.
I have to admit - I've used them on a number of occasions, and they've been very useful. I've used them to get a choir closer to an orchestra, or as extension to existing risers with great success. Many churches for example don't have a good set up for choirs, so these fit the bill in a pinch, plus, you can create a stage anywhere, and in any formation you like.
The problem I have with them is that they look horrible! I've had at least one complaint after a concert from an audience member about them, and I find the more and more that I see them in a concert, the more I dislike them. Certainly as a chorister who has had to stand on one (actually I use two, one for each foot) they are probably the most uncomfortable options around, with no ability to "move" your feet. I also suffer from on stage vertigo, something I picked up a few years ago, and can't seem to find a way to solve, so standing on a plastic stool no wider than my shoulders certainly doesn't help!
My questions is - is there another option? Should someone approach the rubbermaid company and have them create a stool specifically for this purpose? Perhaps a larger, yet still stackable portable system that came in a variety of colours to match the stage?