Today I rode in a Marquis and I had some interesting comparisons between it and my LeSabre.
Both of these cars are full-sized American sedans, on the "sort-of-but-not-quite" point on the luxury spectrum. Interestingly, I've noticed non-car-nerds often look at my car and immediately associate it with the Panther platform, assuming it's body-on-frame and rear-wheel-drive, which it isn't. Hmm.
I'll start this out by saying I have no idea what the trim levels are for the Grand Marquis, but I do know my LeSabre is moderately-equipped, with some of the fancier things like heated seats, HUD, CD changer, etc. missing.
The LeSabre has a failing A/C compressor, the Marquis could probably create ice. Even when the LeSabre's A/C was working perfectly it wasn't that cold. Damn.
The Marquis had more rear leg room.
The LeSabre had far comfier seats. They were leather in both cars, but the Buick just seemed more warm and friendly. Especially the back seat.
The LeSabre had far superior speakers, though I'm not sure if "high-end" speakers were installed on the Marquis.
They're both horribly slow. Despite its much larger V8, the Marquis was slowed down by its heavier body-on-frame construction.
Result: Both powered by anemic hampsters
The heavier Marquis was more floaty. No contest.
The heavier Marquis didn't go 'round corners. At least the LeSabre was controllably understeering
Neither car is really better than the other. Both are large, slow, comfy cruisers with a slew of aftermarket modification options due to their platforms/engines, and they both look... whatever.
Personally I think the Buick makes more sense. It gets 30mpg highway vs the Mercury's 25mpg (both get 17 city), the 4.6L V8 only makes 30hp more than the 3.8L Buick (235 vs 205) and 60ftlb of torque, the car weighs 600-700 pounds more.
The only situation where the Mercury makes sense is if you have mods in mind that require body-on-frame, want to do donuts because RWD, or if you're just a purist that insists body goes on frame with an engine in front and drive wheels in the back spinning uselessly because there's hardly any weight on them.
I'm slightly biased.
I'm not sorry :>