[Neanderthal]

Got rid of the 2004 Impala and bought a first-generation Chrysler LHS.
Why?
Why not?

Driver environment:
LHS leather interior is first rate, very classy looking, feeling, and smelling even after 12 years @3,000 miles/year. The seats are comfortable rather than the chiropractor-lobby-inspired devices in the Impala. The Driver Information Center is a fun toy, it precludes my having to do the aftermarket bit to get compass/temp. And the instant and overall MPG feature is just the thing to get me into a rear-ender.
No worries with the dash, it's missing dual zone and if I were dictator for a day DZ would be in every car sold in Amurricar. It does have auto temp which IMO is way overrated, but WTF engineers have to do something with their spare time other than designing a fresh air intake filter system--which no LH car had apparently--and doing DZ which I guess Chrysler never did understand.

Driving:
Thank God someone understands suspensions a bit better than the goobers at Impala Inc. This makes up for the no DZ and no cabin air filter.
This car has had a few suspension bushings replaced, but the struts and anti-roll bars are original equipment and about, oh, 12 to 24 years ahead of the Impala.
I don't know if the 2006+ Imps suspension is as squishy as the 2000-2005 generation, but I replaced the Impy struts at about 12 thou with KYB GR-2 and although they did away with the worst of the narrow-rowboat-on-a-choppy-lake feeling, the Imp really needs Konis or something just this side of them firmness-wise, as well as the GM Parts Direct HD anti roll bars. The struts are weak and the car rolls far too much in light curves.
My LHS has nicely snubbed jounce and rebound while providing a comfortable ride. The well-dialed-in anti-roll control keeps her flat in the curves and corners.
Again, I don't notice much difference in the highway comfort level, but the well-controlled ride motions in the Chrysler are head and shoulders above the Impala's squishmobile standard.

The 214 HP 214 TQ first gen. Mopar 3.5 OHC has plenty of scat. It should, geared as low as it is: 30 MPH/1000 RPM in top gear, as opposed to the Chevy's 36.5 thanks to a 2.86 final drive vs. a 3.66 over at Chrysler Corp.
I wonder how close a contest it would be in the 1/4 with the 3.4 Impala geared as tight as this puppy? Maybe not too close, the Chev power gets flat at 5000 or so while the Chrysler just keeps giving at the office, right past 6000 and on to redline.
Chrysler doesn't get it with gearing like Chevy doesn't get it with suspension settings and seats. Torque peak is somewhere around 3000 RPM, lower than the 3.4 and 3.8 Impalas, and this thing gits it from low to yo! and snaps into third gear at WFO before you can say lookee the cop.
I'm not expecting the great MPG I got in the Impala. I did get close to 30 during a 55-65 MPH cruise for about 30 miles when I was road testing the new plugs. It came with the original plugs--no extra charge--and I felt no difference with a fresh set in.

Four wheel discs and ABS are both standard on the LHS, as they should be on every car. No problem with the brakes, I try not to use them anyway, just a waste of saudi's finest fuels.

Looks: This is subjective except for the various experts who have All Encompassing Knowledge and can claim with impunity "that sucks!"
I am one of the two dozen or so natural born US citizens who consider the 00-05 Impala a fairly handsome car. I like the overall look, like the front, like the taillight treatment. I think the new ones got the blanderizer treatment, making them one with the UJCS (Universal Japanese Car Standard) of invisibility. But hey, maybe they're getting lots of FBI contracts or something.
Oh yeah, looks. I think the LHS of both generations are good looking, distinguished actually, in different ways. The impression of course is dependent on the car's color. They look best in black or white, IMHO. Mine is gold, or a 60s-70s Army OD green in low light conditions. Then it looks like a general staff car, especially with the black steel wheels and snows it's wearing for the slick months.

The LHS looks much lower than the Impala, although real height is different by 3" or less. The roof is lower, the hood is lower, the trunk is like way down there.
It's lower, wider, longer, has a real spare tire and enough leg room in back to put a couple of old Checker Cab jump seats back there in a pinch.

So: Far quicker acceleration, poorer MPG, better handling, a draw braking. A far friendlier set of chairs, a real spare, it lacks a cabin air filter which I will try to improvise, and it sits lower with a far lower lift over for the trunk.
I'm happy.