While the Mazda3 has generally been well-received for its sporty design and engaging driving experience, there are a few model years that have been associated with certain issues. Specifically, the 2010 and 2011 model years have been noted for potential transmission problems, including issues with shifting and hesitation. Additionally, some users have reported rust problems in the rear wheel wells of Mazda3s from the 2004 to 2009 model years, particularly in regions with harsh winters and exposure to road salt. It's important for prospective buyers to conduct thorough research and consider individual vehicle histories when looking at used Mazda3s, as maintenance and care can significantly impact a car's reliability regardless of the model year.