I have the Cortina travel system and LOVE it.
Super easy to install carseat base
One of the safest carseats on the market
Stroller stands alone when collapsed
Stroller handlebar folds to save space in trunk and adjusts for shorter & taller parents
Stroller is super easy to open and fold
Stroller seat folds down flat (my infant loves to nap in it)
Carseat comes with infant insert (no need to purchase another one)
When used together the stroller and carseat will completely shade your LO
Cons: I personally don't have any and the only complaints I have seen are "travel system" related (stroller too bulky, etc). We have used the stroller almost every day since our LO was 3 days old and we do not find the travel system to be too bulky.
The car seat is great. The stroller is just OK. The travel system strollers tend to be cheap and bulky. A lot people complain that you can't get to the basket when the seat is reclined.
A lot of people like to get the car seat and either a better stroller like the City Mini, or a jogging stroller or the Snap n go and get a better stroller later on.
We have the Chicco travel system. Not sure what it's called, but it's the "cubes" model. We love it. DD is almost a year old and we still use the carrier and stroller all the time. We don't find it to be bulky at all.
My best friend got the Graco travel system and they are both really great car seats. The one thing that I loved about her carrier was that the sunshade came down all the way to cover the baby's face. That being said, I also didn't realize the Chicco had a tiny sunshade that goes down beyond the big one. It isn't quite as good as the Graco, but it helps. I don't think you can go wrong with either!