I would never get a car that had one, just my two cents.
I used to work at a body shop/collision center and would see many people come in with them because of leaks or other problems. They are okay if you don't plan on keeping the car forever, or are going to have a nice extended warranty.
Just be prepared that they break and are very expensive to fix. I remember people coming in all the time, even with newer cars that had no warranty on them that would cost well over $500 to get them fixed. One time a guy with a newer Monte Carlo came in with one and the wiring went bad and he had no extended warranty - just to replace it - over $2,000
They are nice, yes, but I don't think I'd want to put up with the hassle of them