What I like most is the head height inside, and sitting higher up too - I hate going in ordinary cars now, always hit my head on the roof and feel as if I'm sitting in the road. My kids are years past car seats now but it is much easier (I hear) to get them in and out with a higher car.
Drawback to the Zafira's seating arrangement - on older ones, not sure if it's changed? - is that the middle row of seats doesn't split, and it has to be moved right forward in order to pull the rear seats out of the floor, so if you have a child seat in the middle row (or any other passengers there) you have to remove it/them from the car before you can do anything.
Also, there is nowhere in the car to put the rolled-up parcel shelf when the rear seats are in use - or the bit of carpet that goes over them when they're folded away - so you have to store them in the house - you can't spontaneously accommodate a few extra bodies when you're out unless they hold the parcel shelf and carpet on their laps!
It is a really nice car to drive though (mine is 2.0 DTi)