As said before they work good when you don't have a darkroom available. Actually they work good even if you do have a darkroom available. You can occasionally get a malfunction, I think it is on the average of one for every 400. but you would never shoot one sheet anyways. You can get a holder malfunction as well. It works the same way as a polaroid holder does, so if you get a metal tab stuck at the bottom, it may not be pulling sheets. When you use it, you do have to feel the film get pulled down to make sure it is working.
Other than that, the quality is great, same film as individual sheets.