I doubt the Sportbrake would be more fun to drive than a saloon in any model.
Simple physics.
I think you’d be better with an X260. You may feel the throttle response is a little more tardy but this is down to emissions targets, clearly the X260 is the faster car.

 

I doubt the Sportbrake would be more fun to drive than a saloon in any model.
Simple physics.

There may be a bit more to the physics. A sportbrake has more of it's weight in the rear. And while some front engined and transmissioned manufacturers maintain that 50/50 is the ideal weight distribution (and almost never manage to actually deliver that, despite their claims), everyone else says you want more weight in the rear. Many say 58%. Hence front-engined Ferraris, Masseratis, Alfas, and Porsches with the transmission in the rear.

But never mind the physics, I'm pretty sure I saw at least two reviews saying the X250 Sportbrake was more fun than the sedan. One was Fifth Gear. Though I don't think they knew for sure why, my takeaway from the reviews was that Jaguar had better tuned the newer Sportbrake's suspension.

 

Just to add.
The x260 is euro 6 compliant across all models, good for that ULEZ. The 3.0d in the x260 is 300Ps/700Nm compared to 275Ps/600Nm in its most powerful form in the x250 which is a heavier car too.
x260 - aluminium chassis, better infotainment, and a new improved Suspension setup
X250 - steel, older models have water ingress issues which can wreck the BCM and some have even had water blockage in doors too.

 

... plus, for me, I prefer the interior of the X260.

... and the Adaptive LED headlamps.

And, of course, the 700Nm of torque in the 3.0D engine.

 

I would vote for Mark 2 (model code X260) preferably in 3 litre either supercharged petrol or twin turbo diesel. Awesome cars.

Compared to X250 (the mark 1) the X260 (Mark 2) has a few negatives and many positives.

Bad news first:

• interior has more leather & wood in X250
• X250 rear styling is prettier (less generic)
• split fold seats were standard on X250, optional extra on X260 so check the car has it
• base models don't have full electric seats (so get Portfolio or XF S)
• no v8 options (sadly)
• 2 litre diesels less reliable. Get 3 litre.
• 2 litre single turbo models have worse turbo lag than v6 X250. Another reason to get a 3 litre X260.

Positives for X260:

• handles better (lighter & new suspension)
• looks more modern
• better steering feel
• much better infotainment
• All Surface Progress Control, so copes better with slippery conditions
• better economy, especially in 2 litre diesel
• switchgear more logical - fog lamp works off stalk, drive modes in one button, easy access to temperature controls for passenger
• more room in the back seats
• bigger bootspace
• much better tech (e.g. remote start)
• aluminium doesn't rust
• less obtrusive keyless entry dimples
• bigger sunroof
• ability to do remote monitoring and remote start (most models)
• WiFi capability (although I don't use it)
• better seat memories (in some models - my XF S has 3 for driver and 3 for front seat passenger)

Both X250 and X260 are superb cars. I have had both (still have an X260 XF S Supercharged).

IMHO!