This is more of the brand quality issue than the panorama sunroof issue itself. The panorama sunroof on my brother's 2012 BMW 520d sportwagen has no issues at all! And BMW who always claims its cars are "Ultimate Driving Machine", doesn't think the panorama sunroof would affect performance and efficiency.
BTW, we had a 2001.5 VW Passat with a regular sunroof and absolutely having water leak issues and flooded cabin and trunk many times!
