It's an incredibly well-thought-out piece of equipment, and I love that you can arrange the seats in any configuration you want (both kids facing you, both kids facing out, etc.), and I love the fact that L and C love napping in it. Speaking of, when we were looking at buying the stroller, the sales guy was doing his darndest to sell us the bells and whistles for an infant: car seat adaptor, bassinet, etc. Wary of making yet another purchase mistake, we passed on the extras, and good thing we did, too! For L, the newborn, we just padded the stroller seat with a Bundle Me and reclined it a little, and the moment we put her into it, we knew we had a winner. She absolutely loves it. Falls asleep in it every time. In fact, she loves it so much that, for a while, we were using it for all of her sleeping needs -- naps and nighttime sleeping. So, unless you live in the 'burbs and use a car seat all the time, don't bother with the car seat adaptor or the bassinet.
The downside of the City Select, of course, is the weight. While maneuverability is amazing, I often feel like Sisyphus, rolling that damn boulder uphill (even when I'm on a flat surface). On the bright side, I suspect my arms will be pretty toned in a couple of months.
And then I discovered this: http://kinderwagon.com/.
Ohmigod, did I make yet ANOTHER mistake, buying the City Select? Is the Kinderwagon Hop the double stroller of my dreams? An umbrella double stroller? Genius! But how many more strollers can a family take????