Being able to see your food cooking without having to open the oven door sounds like a small thing, but it's huge. When you include this amenity in your new oven, you'll save money on wasted energy because you'll be peeking less -- and letting hot air escape from the oven cavity. Admit it: You know you look more than you have to. Genuflecting in front of the oven for an eyes-on assessment of your bubbling mac-and-cheese isn't such a bad idea when all you have to do is look through the conveniently placed glass window. It may save you having to insist that the black crust on your apple pie is actually golden brown.
If you've owned a glass-door oven before and thought it looked dirty despite your best effort to clean it, innovations in glass manufacture and glass door design are eliminating problems with clouding and stubborn, baked on grease. Glass cleaners designed for new generation glass stovetops are doing a better job of cutting grease and grime, too.