I had a changing bag... and used it so I do have a whole bunch of recommendations on the subject!
If you choose one, take the model with a tent like design or don't get any at all.
I had the flat model. If you have to use it to open a camera back, the fabric drapes over your hands and you're always afraid to break the camera.
If you use it to load film, you have to be extra careful not to cut through the bag with the scissors. And when loading film on a reel, you have to find a way to keep the fabric from hindering the process... which it will do. You have to put a lot of effort just to prevent the bag from sagging. and when you push the top up, the bottom tends to pucker... extremely annoying.
Also, mine had very tight wrist bands when I first got it. But the wrists were quite short and the slightest move could cause the rubber bands to slip down my arms possibly letting light in.
I got mine used and didn't pay much for it, so it wasn't too painful to leave it on the shelf. Last time I went to use it, the nylon outer shell which is covered with a light-tight black rubbery substance was starting to disintegrate. This made me totally loose faith since it was leaving black dandruff everywhere, including inside the inner bag... Just overly annoying.