I just had a chance to read that last night. I didn't get the picture that the other two were appreciably better other than they were rear-wheel drive. If that's your priority than of course M3 or even Caddy is for you. At the end of the day though these tests are more often than not subjective and as you can see the order was different in Motor Trend. I suspect the RS 5 is still the best day-to-day on the road, certainly the only year-round driver in the mix and easier to drive fast with less skill (admittedly in that article).
The other thing I find is that those with a higher degree of driving skills or training tend not to like cars that are performance levelers. It's kind of like the manual transmission... a right of passage that most of us want people to learn. The RS 5, like many modern Audis, is easy for 'lesser' drivers to drive fast too and, well, if you've spent a lot of money on driver training you may not be that appreciative when someone you view as slow hits lap times close to yours on a track day whereas were you and he had been driving the BMW you'd have stomped him more thoroughly.
I wonder too what would have happened if it had rained while they were at the Ring.