Dont be fooled by the jag, poor interior, poor build on the early ones, general all round sense of cheapness, the 75 is by far the better car.
As driver of both here's my view.
My 75 is an 02 CDT with 105k miles on it, Synergy etc to boost power to 150bhp. My X-type is an 07 estate 2.0D S and standard, has 128bhp.
The Jag is no substitute, but build quality and interior is comparable except for the plastics of the centre console which belong to an Amstrad 'hifi'. The steering wheel has the texture of carboard and has a thin rim and tacky Amstrad radio controls.
Ride and seats are firmer but there is less initial understeer entering a bend. Overall handling and grip seems about the same. The Pirelli Pzeros are noisy in a coarse roaring way.
The engine is quieter when revved and as smooth except around 1200rpm when it can be felt through the steering wheel. The clutch is much lighter.
Brakes lack the 75's initial bite, but otherwise are fine.
The performance is lively with somewhat over sensitive throttle response, whereby 80% of the performance needs barely 50% of the pedal travel. Its the opposite to the CDT, which requires 100% of the pedal travel for 100% of the performance but this more progressive action makes is easier to drive in urban areas.
Overall Jaguar need to address the areas of (relatively minor) critiscm before they can satisfy the majority of former 75 owners. A few quid spent by them would make all the difference.
However, I'll probably spend it instead, and will fit a wood dash kit and wood/leather steering wheel. Toyo Proxes T1R tyres look likely as well.
Centre console and steering wheel quality not good enough.
Fit some decent tyres
Soften the ride and seating.
Re calibrate the throttle position sensor to give a more linear response.
If you can find a used one at a good price and don't mind spending some money on the interior/steering wheel/tyres then an X-type would make a decent British built alternative.
My Tu3 will be available shortly which will boost power to 155-160bhp and torque to 270lbs ft.
I would not let the critiscms put you off.
There is a page on my website with photos.
One major overisght on jaguars part - NO automatic diesels.