A few things I noticed when I drove the ATS that are not offered in the review:
I have driven all 3 of these exact cars, albeit not on a windy backroad, but in a normal city and a normal highway. In other words, I drove then the way I'd be driving them if I owned them.
1. The ATS is loud. Unsettlingly so. The disparity between normal driving engine noise and hard-on-the-throttle engine noise is significant. As in "wow, where'd that come from" kind of noise. It felt as if BMW, knowing people wanted to hear their engine, found a way to insulate the cabin from noise while also allowing enough in to satisfy the driver and Cadillac just kinda said "well, people like engine noise so let's get rid of the insulation between the engine and the cabin, that'll give 'em what they want and save some weight, two birds with one stone, yeehaw!" It is not a deal breaker but it's there. Think of it this way: when you hear a great home theatre system turned up loud, you know it's loud but it doesn't hurt your ears because it is tuned well and despite the volume it sounds good...but with a crappier system it's like "damn, turn that down!". I felt the Caddy's engine noise was the latter.
2. ATS back seats leave a lot to be desired. I am 6'1 and sat in the back seat behind the driver's seat, with the driver's seat where I had it when driving. My knees were not touching the back of the seat, but my hair was brushing the roof. I also found the butt part of the backseat to be too angled in relation to the back part...it gave me the impression that you'd be sitting in an acute angle. But maybe I'm being obtuse...
3. Trunk space...small. Definitely smaller than the Merc and the BMW. You'd have trouble fitting 2 sacks of golf bats in there, and you'd certainly have to remove your drivers.
4. I don't like the exterior design. It is a shrunken Cadillac. If you're not a fan of their design philosophy, you won't like this car. That said, it is the best looking vehicle in their line up...but it still is not as nice looking at the C class or 3 series. Maybe the ats-v will be a bi tmore appealing.
5. CUE is bad. All that hype about it being revolutionary is bogus because it is slow and makes you take your eyes off the road. Touch screens are not good...they get dirty and they distract the driver. Liebrman is right...it needs to be as good or better then the ipad in terms of reactiveness and ease of use. It's not even close. It's the Pentium II of ipads. CUE is Paperboy and iDrive is Call of Duty.
For the purposes of this test drive...the windy back road with no other traffic, maybe the ATS is the best. BUt most of us drive on normal straight roads and normal highways with lots of other cars and when we are doign that we don't want the jarring of a stiff chassis, and we can't drive hard enough to notice body roll or chassis stiffness.
The reviewer seemed to ignore all the interior stuff he spends the first half of the video explaining, and makes his decision almost entirely based on the backroad experience. I would argue that the difference in driving experience between the 3 cars is far less than the difference in the interiors...which is a lot different. So if driving dynamics in the ATS are a 9/10 and in the 335i it's 8/10, the cabin experience in the ATS is like 6/10 and the 335i is 9/10. Cumulatively, in my books anyway, that would give the 335i the win.