I bought a Kenmore electric range with a glass top, which cracked after four months. Nothing hit it, it just cracked in half by itself.
I called the Sears warranty people and was told it was a "thermal crack" and was covered by my one-year warranty. We set up a date for the repair: Thursday between 8 a.m. and noon. I took off work on Thursday and at 15 minutes past noon the repair man called and said it would be $129 for his visit plus $250 for the part.
I said it was covered under warranty and he replied "No, 99.9% of the time the crack is the homeowners fault and I am the one who determines fault". I told him to kiss my a$$ and called the Sears warranty phone people back, asking to speak to a manager. They put me on hold and 50 minutes later I was still on hold, so I hung up. A lady I work with suggested going to a Sears store, and what a great idea it was.
They took great care of me: They came and got my stove and installed one without a glass top.
I will never buy a glass-top stove again. So glass tops on ranges suck, the Sears phone warranty people are horrible, the Sears repair people are horrible, and the Sears store people are great.