Quick, responsive, go kart-like handling. Super fun in corners and curves. Great connection between car and driver. I always felt a tremendous amount of control, even when going a bit too fast through corners.
Bulletproof reliability reputation with very few issues over the life of the car. Miatas with 200,000 miles on them are not uncommon.
Great value for the car -- Used, I could get a fully loaded sports car for the same price as a new base model economy car.
Thoughtfully designed to make the most of cargo capacity in a small car. There are lots of little touches that optimize storage space and fuel economy, as well as making it feel like a luxury car.