Here is my opinion. It is based on driving every train combination available in the Mazda3 in the US, take it for what it is worth.
The Mazda3 with the automatic ran well and the manual mode of the transmission worked well. Left to itself, the transmission shifted smoothly and quickly up and down through the gears. When being sporty, manual down shifts under braking for a turn did not upset the car. These down shifts did produce a decent amount of engine braking and should be useful for controlling the cars speed coming down a mountain road. Manual up shifts also worked well. Up or down, the shifts do seem to take a little while once you select the next gear. It also seems that Mazda has built in the same pause in the 1-2 and 2-1 gear changes that are in the Mazda6 auto. These result in a drawn out shift between these gears even in the automatic mode. The sport auto is a decent compromise but not a replacement for a manual.
The manual was excellent, for a standard sedan. The clutch pressure was light with a reasonable amount of feel and easy to manipulate. The shift linkage was short, quick and easy to find the gears. The gearing provides a lot of overlap between gears. 2nd gear could be used down to a very low speed while 3rd allowed you to go as fast as traffic normally would let you. This set up meant that you only needed to use two gears most of the time in the traffic. If you have to stop, then you do need to use first gear. With either engine, the manual worked well. Compared to the 2.3, the 2.0 required more RPM to go quickly but did so with little or no drama.
Although nice and improved, I much prefer the manual to the automatic. If I had to have an automatic, I would get it with the 2.3 liter engine. This is a much happier and responsive set up than the 2.0 auto.
I hope this helps you.
