I've got a rental Optima at the moment. I'd get the Buick.
The seat was designed by airline manufacturers, it curls you over and has your chin firmly on your chest. Yech!
One of the goofiest throttle by wires I've run into. As near as I can tell, it's programed to hold the given vehicle speed with just the faintest touch. There is no need to hold the pedal down to do 80, or 20. Just touch the throttle once the speed has been achieved. Almost forces you to drive with the cruise control instead.
With the rear seat headrests and small vertical height, there may as well not be a rear window. Turning to look just lets you admire those headrests, you can't see anything over there.
Engine performance is flat, until it explodes with power. Makes pulling out of gravel driveways without spinning the tires all but impossible.
Brakes feel like they are regenerative, but they aren't.
6 speed auto tranny can't decide what gear to chose, and spends a lot of time feeling like it's shifting, or locking the torque converter, though none of this shows up on the tachometer.
Front end is banged up on this one. Lady who rented it to me told me everyone runs into things with the Optima, apparently because you can't see any of the nose. You just guess as to where it is.
