I have a sunroof on both the Saab and the Infiniti. In winter when the sun is shining I have the sun shade open. It warms the interior nicely. In the summer, I use the vent feature a lot, especially one hot summer days. I notice it helps the AC out by cooling the interior faster, since hot air rises. I thought about buying the MB with panoramic roof, however after looking at the mechanism, I decided the expense to fix it out of warranty-should anything go wrong, would be too much.