The glass cover fits snugly enough that I don't bother with foil anymore, and cleanup is just a quick soak. Made a big batch of scalloped potatoes in the deeper dish last night and it went straight to the table without dirtying another pan.
Watching the layers brown through the clear sides means I've stopped guessing when the middle is done. The glass lid doubles as a serving piece too, so it goes straight from oven to table without dirtying another dish.