Funny how these seem to get [censored] on, especially by people who have never owned one.
I bought mine in 2008 with 56,000 miles on it and it has been my primary daily driver since then. The car is now just short of 153,000 miles. Nearly all of those miles are mine-I doubt it's had more than 300 miles with someone else behind the wheel.
I'd hop in it today and drive it to California if I needed a reason to do so.
I have the 3.9L V8, which is the Jaguar-shared engine. I've been running Mobil 1 5W-20 in combination with a Motorcraft filter for 10K miles since about 70K. Before that, I did Motorcraft 5W-20 for 5K.
I have done very little outside normal maintenance. You can expect to start losing ignition coils at around 110-120K miles and they are a bear to change, but should be good for a while after they have been done. Replace all 8 while you're in there as getting access to them is the most difficult part. Some cars had problems early in life, and Ford actually extended the ignition coil warranty to 100,000 mile. It's worth checking if this was done, since the warranty repair was to replace all 8 coils-not just the bad ones. BTW, a failing ignition coil will often throw a throttle body code rather than a misfire code. The #1 and #5 coils seem to be the first to go bad, and the stray RF from them can make the car think the electronic throttle body is malfunctioning. This is a common mis-diagnoses and I've know folks who spent big bucks on a replacement throttle body that wasn't actually needed-the throttle body in normal use is a lifetime part.
I lost a window regulator a couple of years ago, and finally had my mechanic change it because it was so difficult. I had to put new tie rods and tie rod ends on it this past spring because I think the salt had finally gotten to them-they weren't unsafe, but the shop couldn't get them loose to align them after a tire change. I had a radiator hose blow on the interstate that left me having to have it towed.
The recommended transmission service interval is something obscenely high-I think 100 or 150K. There is a Ford engineer on the Lincoln LS owners' club website who is pretty adamant about a 30K interval on this. The transmission doesn't have a dip stick plus a drain and refill only gets a small part of the fluid. I have the local F/L dealer do it(one of the few pieces of maintenance I don't do myself)-it's around $250 for a flush.
My A/C went out a couple of years ago. That was not cheap to fix, but it should be good for a while. The compressor was bad, and both my regular mechanic and a few other places I called said that they could only warranty it with a full system replacement. I know my mechanic well enough that he brought me in to look after he'd pulled the compressor and it had pretty well ground itself into oblivion and left crud in the lines.
The car absolutely drives like a dream provided that the suspension has been maintained. When I did the tie rods, I took the chance to renew the A-arms and ball joints all around, which made a noticeable difference in the handling. The car was designed to compete with the BMW 5-series, and IMO they did a pretty darn good job at least in the handling department. A stock car is dead-on 50:50. It has fully independent double wishbone rear suspension, and of course the same in the front. Just watch the garages and make sure they don't try to jack it by the differential!
BTW, the AJ-V8 made Ward's top ten list in I think 2000 or 2001. The revision introduced to the '03 LS added variable valve timing.
The LS is totally unlike anything the F/L/M group had made before or has made since. It's was a clean slate design and the only mass parts sharing was with the early 2000s Ford Thunderbird. Although the basic AJ-V8 design was shared by Jaguar, it only made it into the LS and T-Bird on the Ford side of things. The 3.9L version is unique to F/L.
My overall cost of ownership has been very low-it's not the money pit that someone above suggested. My only major 2016 expense was a new set of tires-$800 for the tires and around $200 for all the suspension parts I replaced. Aside from oil changes, a coolant flush, and brake pads the only repair work I did in 2015 was a serpentine belt that cost me about $40 at NAPA. All told, I think my maintenance was $200 for the year. If I said down and figured it up, I'd guess I've spent about $800 a year on average maintaining the car, and that's including wear and tear items like tires and brakes. I'd call that a pretty darn inexpensive car to own.