Beautiful car indeed, but German engineering trumps anything Detroit has to offer. IMO of course
You need to drive the ATS. It has the better chassis than the 3 series. Especially since the F30 got even softer. You're doing a disservice if you're just going to go off perception and not form your own opinion after driving both.
I will miss the N54 and the ZF 6 speed auto that was in the 335xi, but the 3.6 liter V6 and the GM's own 6 speed auto isn't bad either. But the ATS handles better and more enjoyable to drive on the back roads. Also prefer the interior in the ATS over the 3 series as well.