Go ahead and succumb to the lure of "Grace, Space, and Pace" if you want, but be aware that...
"The 6-speed trans has suffered from a series of electronic glitches, causing shuddering, noise, and a tendency to hang onto gears too long when decelerating. There have been several ECU upgrades which should have sorted most of these symptoms, but problems my still remain on some cars."
"An unusual problem relates to the electronic handbrake used on the later cars; it seems that the original actuating motor had insufficient travel to clamp the disc sufficiently once the pads wore. Replacement motors have been designed with extended range."
"The S-Type seems to have a healthy appetite for batteries...there is noticeable current draw for up to half an hour after the key has been removed. Common problems include corrosion of the wiring loom where it passes through the front wheelarch."
"The dual control valve, which varies the coolant flow to each side of the heater unit according to the temperatures set, can eventually seize up regardless of the coolant type used, and will often be the first casualty if conventional antifreeze is mistakenly added to the cooling system." [A replacement dual control valve is listed at 145 British pounds, BTW.]
Info from "Jaguar World Monthly," March 2007. Y'all want to hear about the front and rear suspension issues? How about the "collapsed water pump impellers, stuck thermostats, and poor quality timing chain tensioners" on the early V8s? (In fairness, the 4.2s are supposed to be better.)