I thought they were called moon roof here - when I got my new car I remember chuckling about that. Having had a car with no moon/sun roof and one with I personally far prefer to have the moon roof. It's lovely at this time of year to have it open for the cooler air in fact last night it had a brand new use -I was out with my friend who is visiting and she wanted to take a picture of the meydan blue flyover so I opened the roof and she held her camera up as we drove past and she took the most awesome picture!!!!!
We have both a car with sunroof and a convertible,
Firstly my kids call it a moon roof here as that's when it's nice to have open on an evening my DS loves looking at the stars or up at the lights on buildings in town so nice then, and no it's never leaked, ever !
My convertible has never leaked either as it has a hard roof , except , it's booked in garage sat as I stupidly left a bottle of windex on roof other day and attempted to open it , the windex rolled into the mechanical workings of roof, made a crunch sound and now won't shut properly :( I'm in the good books with DH as you can imagine ! Oops !
If the car you like has sun/ moon roof go for it I think it's nice to have open in winter