Cars almost always make you compromise somewhere, and with a small car that can be in its practicality. The Mazda2 is no exception. I'm a bigger guy, and while I didn't feel cramped while driving the Mazda2, there's no way someone my size could have ridden behind me. A shorter person might have been OK, but either way it's a tighter fit back there than it is in a Fit or Nissan Versa. (Check the photographs to see how child-safety seats fit, in case your passengers tend to be toddlers rather than adults.)
On the other hand, the cargo area is surprisingly large. In some hatchbacks, there's just not a lot of room behind the rear seats to put stuff. Such is not the case with the Mazda2. I easily fit all the gear I needed for a weekend away in the hatch area without having to fold the seats over. When I did fold the seats, I found I had enough room for my large cyclocross bike without having to remove both wheels. That's nice, because it means the Mazda2 is competitive with the Fit and Versa in the bike-carrying department. The stats show the Versa and Fit are much larger (the Fit has 57.3 cubic feet of maximum cargo area, the Versa has 50.4 and the Mazda2 brings up the rear with 27.8). What I found, though, was that the Mazda's space is usable. In other words, there isn't a ton of vertical space, but from side-to-side and front-to-back, there's a lot of room.

Overall, it's a handy car, but I think it's best-suited for young couples, singles or people with children who are still in car seats.