I use them in electric roasters. They are very nice.
They can melt to the side of the roaster though. Putting a little bit of water between the roaster and the metal pan insert tends to help with this.
Howeveer, WARNING....if you put water between the roaster and the pan, be very very careful. I know a guy who ended up with 3rd degree burns because he picked up a roaster and the water slopped out onto his hands. You don't need very much.
But...yes....the bags are very nice.