I quite like this notebook, and in fact I think it would be an excellent choice for choral singers. The rings are smaller than those in a 1-inch binder, which should make it more compact, or at least slimmer, in theory. But it's still as thick as my cheap old 1-inch binder, which means I can't fit as much sheet music into it, and it'll still take up as much room in my bag as the one I'm replacing. Also, the dimensions are longer than standard binders, so if you have, for example, a pouch in a guitar bag that's designed to hold a notebook, this might not fit. That wouldn't matter to me if I were a choral singer with no other gear to haul around, but for those of us who carry an instrument, compactness is king.
But that's not my reason for taking a star off what would otherwise be a five-star review. Where this notebook falls short is in the little pouches on the inside. They're too small, and I had to spend a moment stretching them out with my hand just to get them to a point where I could put a sheet of paper in there without bending it. That and the fact that it's as thick as my old binder despite having smaller rings and fitting less sheet music.
All in all, it's a fine product, comes with a little strap to keep it closed and a carrying handle. If all you need to carry into a gig is a single notebook, or a notebook and something small and compact like a flute, then this is a great choice.