I like mine - super light, super easy to fold, stands up solo when folded (which is brilliant at bus stops). Can truly be folded with a single hand in seconds. I really like it.
I wouldn't have got it without the carry cot though, worth its weight in gold.
DS adored it and would sleep in restaurants with the hood tipped down. It also unclips to make a very handy travel cot for when they are tiny.
I bought a compatible car seat and found it a nightmare - well the seat was fine as a seat, but I never once used it on the buggy. It was very difficult to get on and off, and was quite hard to install in the car so I never bothered to take it out.
However I think they have changed the way you attach the carseat to the buggy now, so possibly it has improved. Still, unless you have a hugely car-oriented lifestyle I wouldn't bother with it, I'd just get the other bits.
One other tiny con is that there is a bit of an awkward transition from the carry cot to the buggy, unless your child is a tiddler. DS started to outgrow the carrycot at about 4 or 5 months and was frankly bulging out of it by 6, but the buggy is still pretty upright for a 5 month old. We padded his with sheepskins which helped. It wasn't a major issue, but I would have preferred either a bigger cot, or a bit more of an incline on the buggy.