I bought the Snap n Go when we took our 2 month old to Miami. We wanted a cheap stroller to travel with, so we wouldn't mind if it got broken. We gate-checked it and had no problems. (Granted, we were lucky--we might have wanted a canvas bag to stick it in.)
6 months later, it's been one of my favorite purchases.
I use it every day for quick errands in town, trips to the mall, dinner in some restaurants, even in the grocery store--it's easier to push her in it than to lug her into the store and put her in a cart. I just carry my reusable bag and fill that with groceries.
Especially at first, when she almost always fell asleep in the car, it was GREAT not having to wake her up--I'd just move her carseat into the Snap n Go, and she never noticed.
I have not had any problems with durability, although it's clearly not meant for rough terrain! I'm on sidewalks, in the mall, in airports (three plane trips later...), etc. It can "stick" going over bumps or rough patches (some iced-over snow on a sidewalk, for instance)--but I'm not on those surfaces very often, and the convenience of the snap n go far outweighs the few moments when I have to shove it over a small obstruction.
I also, now that my monstrously tall daughter is about to outgrow her infant seat, am very glad that I did not purchase one of the "travel systems." I'm looking for my "next snap-n-go"--the stroller that I will keep in the car and use for errands, plane trips, and the mall. I'm glad I'm not stuck with one of the strollers that comes with an infant seat--they seem to be either very bulky with the infant seat attached, or cheapish and plastic-y, or with other features that I've now realized I don't want, or without features that I've now realized I DO want.
To keep at home, I have a heavy-duty, durable stroller with good suspension for walks around our neighborhood (no sidewalks, and some unpaved roads).
I like the advice from the Baby Bargains book--get whatever car seat you want and the Snap n Go. Use those for a little bit while you figure out what you're going to be doing with your stroller, and then you can make a more informed decision. I thought my big Maclaren was going to be my stroller--until I had to lift it in and out of the car too many times. At the same time, I needed something pretty rugged for walks, so I just gave in and decided it was worth having two strollers for two purposes. People who live in an urban environment might want to ignore my advice...
(and oh! The other two top purchases were a Hooter Hider (sounds crazy, but if you nurse your baby and don't want to sit at home or go into exile every two hours, it's a HUGE help) and a bouncy seat--it's what she sits in when I shower, or do anything, really, when she needs to be secured and I can't hold her.
Good luck.