I have had my Mazda 3 for about a year and a half now, and love it! It is very responsive and fun to drive. Driving it feels "sporty", unlike other cars I test drove (the Nissan Sentra for example). I also felt like it had more interior room and better visibility than the Civic. It would be nice if the fuel economy was a little better, however, I still usually get about 28 miles to the gallon (suburban driving), and on road trips it averages about 31.
Very peppy - fun to drive! Lots of storage space, cup holders, etc.
Truck unlock button on key fob. Larger visors. Be able to open front passenger door by just pulling handle, not having to pull lock first. But, these are all nitpicky things. I love this car!