I have just bought a quinny zapp for my son who is 3 years old. I had read the guides on here beforehand and was a little put off by some of them however i really love the quinny zapp.
The pushchair is so stylish and is the easiest pushchair to push! my son is 3 so the pushchair is not used all the time however he loves it, he sits comfortable in the chair and i am impressed by the harness with its comfortable padding as he is usually reluctant to wear a harness.
Last week he fell to sleep in the pushchair and was comfortable as i put up the hood and he rested his head to the side on this. I personally would not buy the pushchair for a young child who still has day time naps as i prefer a pushchair which lays down however for us it is perfect as our son is usually awake all day.
As for the fold i must admit it takes a bit of getting used to but once you have mastered it i find it easy, however like many other i can't do it with one hand although i keep trying.
I have used the pushchair on public transport bith upright and folded and have not encountered any problems with this at all.
I love the carry bag and we use this in the car when out and about although the pushchair is not that light so don't think you could carry it around with ease. This has not put us off the pushchair as you can tell it is well made which is why it may be heaver than a standard stroller.
Personally i find this pushchair much easier than the stroller we had as i can push it so easily, i also find it useful when we go swimming as it fits into a locker so I know it is safe while we swim.
I hope you find this guide useful and i would be happy to answer any questions by e mail