just went to Honda showroom to test drive the all new civic today.
in term of power yes it is impressive because of turbo kicked in at 1.7K with full torque. somehow the things bothered me were the engine noise and CVT, it is way too loud when it rev up to very high RPM.
BUT in term of stability and handling M3 really doing very great! i would say mazda really put in alot of effort in this among the japanese C-Seg car. For those ever drove the Gen 9/8 civic then you will feel about the same in this new civic perhaps just better?
Although it just a test drive, the overview just based on my opinions.
The things i like in Civic1. Turbo
2. Electronic brake system
3. Mirror Link infotainment
4. Spacious
5. wider vision
Things that i dislike1. No fordable seat
2. loud engine noise and CVT
3. Suspension little bit soft, unstable when drive through some uneven roads with high speed
my opinion and no offence. let me know your opinion of these two cars.

I have tested Civic turbo and Mazda 3, Civic turbo is powerful but very poor in engine sound insulation compared to Mazda 3. In short, the Mazda 3's overall driving experience is closer to continental car like BMW and Audi.
I always have the feeling that Honda car always spec up what people can see on paper or in the car, but cut a lot what you can't see. I hope I am wrong.