I looked into these quite seriously about a year ago. They had just (slightly) revised the range, the biggest change being that the middle row could split 40/20/40 and had 3 proper seat belts. I was looking at the 'design' trim which had replaced the 'comfort' and had all the toys and practicality features you needed. The 1.8 seamed the best engine choice. The Diesel was more expensive but was only slightly more economical and the 1.6 was slow. (didn't consider the 2.2 as it was more expensive and a lot less economical)
The rear 2 seats were ok, but getting access to them was a pain. Although you could tilt the middle backrests forward, the easiest way into the back was to slide the whole middle bench forward which meant everyone getting out. Also with the rear seats in use you have virtually no boot space. The middle row is also quite tight for 3 people (being based on an Astra) and you can't get 3 child seats in if needed. It's also not that good as a tow car as it can only tow upto 1100kg, oh and our local Vauxhall garage was pants. On the plus side it drove well (for an MPV), was well equiped (air-con on all models), and looked like it would stand up to a good battering by the kids.
In the end we went for a Fiat Multipla. Six full sized seats and a decent boot, plus all the usual flexibility to move/remove individual seats, and the kids love sitting up front. The Zafira is a very good car, it just didn't quite suit our requirements.
Thanks.
Steve.