I have a 2015 Lacrosse 3.6. Biggest complaints:
1. The A-pillars. I've learned to move my head to look around them, but it's very irritating and dangerous. They do create blind spots.
2. The front brakes shudder under high speed hard (but not panic) braking. If you push hard enough on the brake pedal the shudder goes away but you don't always want to do a panic stop. The rotors aren't warped (don't pulse and they have been checked) and the pads are good (they too have been checked). This was an issue on my 2007 Lucerne also. Fixed it by putting slotted rotors on the Lucerne. Might have to do that with this car too, but the brakes are in excellent condition still, so I don't really want to spend the money.
3. Slow shifting. At wide-open throttle the shifts are sloooow--the trans doesn't slip, it's just slow. This happens when letting the transmission shift itself and when shifting it "manually." I don't drive it WOT a lot, so mostly it doesn't bother me. But when I do drive hard, I want crisp (not hard, just crisp) shifts. But speaking of manual shifting... the console lid really is placed too high and interferes.
4. The DIC. I get that stupid message that tells me to stop looking at the DIC... which I wasn't looking at until I got the message. Whose idiot idea was that? Also, sometimes it doesn't respond to touch when you try to send a pre-programmed text message. I like to send people a message telling them I'm driving and can't respond--just two quick taps. But it's more distracting trying to get the screen to respond than it would be to just send a text message on the phone. I just call them. That works fine.
All-in-all it's a nice car. Smooth ride, quiet, reliable, mostly comfortable (I have a very bad back so nothing is comfortable for very long). It could use about 50 more horsepower, though. My wife drives a Regal turbo and it's quicker than the LaCrosse, a fact she doesn't let me forget. And the adjustable steering wheel could come out a couple of more inches. Plus it irritates me that it uses the same cheap steering wheel adjuster as a
Chevy Cruze.
I don't understand why people don't get better gas mileage with their 3.6 engines though. Mine averaged over 32mpg on a recent trip from here (Missouri) to California and back. In Kansas, on a 65 mph two-lane highway, it got 36mpg (very, very flat with no wind to speak of). That was what the computer told me anyway. I didn't note mileage/gallons and do the math. Around here, 22-28mpg is usual in a mix of town and country driving (we don't live in a city and do live outside of town a ways).