This is one of the best roadsters you can get. I was debating between this and a S2000 but found the M to be a better "driver" car for me. The S2K has to be raced all the time to have fun and unless you have it over 6k it is pretty slow (unlike the M where you hit the gas at any rpm and it goes), I will say it does handle better but not by much.
A few downsides I have found with this car (most M's) are the glovebox door rattles which is an easy fix, the screen for the subwoofer rattles and the stock subwoofer tube thing sucks as well. And the plastic rear window which is unavoidable for how top comes down, it will get scratched.

The M definately has more features with the interior and just fells nicer than the Honda. Again you are comparing Japan vs German what's your preference? Yes that is Diamond plate floor mats, no I am not trying to "keep it real" but I have grown to like them, they clean real easy.

While this car is plenty balanced I felt the need to step up the HP/Torque by adding a new intake and Sharking the computer, yes it does make a bit a difference and of course raises that redline to where it should be. It sounds beautiful when you open the throttle, I haven't found the need to open the exhaust Because I didn't want this car to sound like a racecar all the time, it is nice to have the top down and have a conversation and not always hear the exhaust. I can hear the engine plenty when I want to.

The wider rims/tires 245 front, 265 rear make this car a lot easier to correct when you get the back to come out though it does also make it want to come out a little more during those decreasing radius exit ramps (may be it is because the rear tires are almost bald too).