I bought my 2007 Mazda 3 In august 2016. This is my first car so I generally wanted something fuel efficient and reliable. When I bought the car, it had 115,000 KM's on it and now has almost 120,000 Km's on it.

The Good: The car is very cheap on insurance and is also pretty good on gas. The seats are comfortable for around the city trips and the suspension gives an average ride you would normally expect from an economy car. The running costs for regular maintenance is relatively cheap/average. The Mazda 3 also has decent cargo space.

The Bad: The car has been nothing but trouble. The car has had reliability issues ever since the day I bought the car. I had to put all new rotors and pads which is just regular maintenance. But, I had to replace the suspension, put in a new battery and alternator, now the Air Conditioning system is having issues. These cars are also famous for rust under the car, which my car unfortunately has.

Overall, The car has good storage space and is good on gas, but has rust and reliability issues. If you are going to buy this car, I would recommend buying a model with an manual transmission.
I own a 4 speed automatic version, and on the highway the engine sits at relatively 3000 rpm in 4th gear. I am not sure if I would ever consider buying another Mazda, but that is just my opinion and it will vary from person to person.