My Grand Marquis I inherited in 03. I didn't use it as a "reap the benifits" situation. Rather I had always loved it, and was familiar with its regular maintenance and careful driving.
The basic setup is great for a conservative person like myself. It has all the standard equipment you'd expect in a modern car, along with some good extras like above average front / back seat illumination. The digital dash is great too. It has some nice displays like average and instant m.p.g., outside temp, tach and distance to empty. It's not "loaded" as in todays standards with extravagant features like GPS, MP3 input and other lavish unneeded adds. I prefer it this way, although I may throw in a CD player in the near future.
Also a great thing most people don't check for on cars is the EDR blackbox. My year doesn't have one and I'm happy to be able to say Ford or Big Brother can't watch my moves.
The additions are great. The A.C. is nice and cool, while the heat is perfect. All the controls are again conservative in appearance, but do justice for being within good reach of the driver.
Road feel is a little loose at high speeds, but its great for parking for its abundant size.
Performance is great. While I'm very light on the throttle, it's very easy in return. But if you throw it down, this car will run! After some moderate wheel spin off the line (dual traction in these conditions), the engine note through its long gear ratios, makes good music all the way to 100. I really haven't gone past that. But the torque supply is there all the way.
Braking feels tight. Almost as if there's no ABS. And aside from pretty noticeable brake fade, it's great!
The ride isn't really wallowy as you'd expect. Turning the air suspension off makes a little more pillow feel out of the road.
Gas mileage used to be 19/23 for me, which is dead on with the EPA estimates. Now with some research into the right additives (acetone/xylene/pri-g fuel additives) (tufoil engine additive) I get 23 city and 29 highway. Winter gas brings both down about 2 1/2 mpg's.
Either way it's a superb car and really faithful. While most describe it as a boat or granny car, I kind of turn off those comments. I look at it in terms of old fashioned quality engineering (iron block V-8 / body - on - frame structure!). I would hope more go for these cars as they are very much underrated!