If there's one thing Jaguar does very well, it's make you feel good about yourself, your car and the world out there beyond the bonnet. It does it like no other. Take this XF 2.2 Diesel Portfolio I'm in just now. This isn't just driving, this is a motoring experience.Jaguar is very proud of this car, and so it should be. It's a genuine luxury saloon; large, powerful and imposing, and it can be viewed through a prism of the company's sporting heritage. And yet it's offering fuel economy on a par with many more mainstream family cars.This is a genuine prestige automobile, packed with technology and feelgood features and weighing in at over 1.7 tonnes, yet it's got official combined fuel economy of 52.3mpg. That's similar to a two-litre diesel Mondeo or Insignia. Oh yes, Jaguar has a very good reason to be proud of this car.The XF range has just undergone a bit of a revamp. The biggest external change is to the headlamps which have lost that wild-eyed stare that straddled genius and madness, in favour of a level gaze that, to me, conveys intense concentration and perhaps a latent threat.The car's still sleek and elegant with a big mesh front grille, long sweeping flanks, an indisputably sporting line to the roof, the slickest rear light cluster this side of Aston Martin, and a power hump on the bonnet that's delightfully visible from the driver’s seat.Spec levels for the XF climb from the relatively basic SE to Luxury (which sounds like it should be the top of the range), on up to Premium Luxury (surely we've reached the pinnacle of excellence and opulence), then up another final rung to Portfolio. This car is the Portfolio, which would cost £43,050 except that it also has £4560 worth of extra kit built in.But you do get a lot of car for your money. A lot of smiles for the miles too.The sense of occasion begins as you approach the beast. It looks utterly gorgeous from any angle so you're already smiling. Keyless door locks makes for a cool entrance and the heated/cooled multi-adjustable black leather seats with pale piping not only look the mutt's nuts but also grip and support you in supreme comfort and security.As you close the door, a blood red light is pulsing like a heartbeat in the starter button. The time has come to wake the beast. Step on the brake pedal, stab the button and stuff starts happening. To the soundtrack of the engine catching and settling in, vents in the facia open up like eyes and the big chrome knob that acts as selector for the automatic gearbox rises with elegant grace from the console. You feel like you should be reaching for the list of pre-flight checks.Turn the knob to D for Drive, drop the electronic parking brake and ease forward into the world. It's a long car (as you'll notice when you're in a standard-size parking slot) so the turning circle is a bit wide, but with proximity alarms and a reversing camera, there's no excuse for not seeing any surrounding obstacles.On the road, the XF is exceptional. The 2.2-litre four-cylinder diesel engine turns out a very useful 187bhp and an even more useful 332lb/ft of torque. This is pumped through an eight-speed – yes eight-speed - automatic gearbox to the rear wheels.There's a split second delay as you stamp on the go pedal, but then the car surges out with gathering urgency. It'll clip through 60mph just 8 seconds after take-off and go on up to a limited 140mph. That's helped by having an S for Sport position on the gear selector (it keeps the revs higher), or by opting to change gears semi-manually with paddles under the steering wheel. If you're in D and planning to overtake, it can be helpful to cock it into S before pulling the trigger on the manoeuvre.I've driven over 500 enthusiastic miles of motorway, trunk-road, country lane and city streets in just a few days and according to the onboard computer, I've averaged a little over 45mpg; significantly less than the official figure but I suppose almost half of that distance was done with a full boot and three adults on board.Allegedly aiding and abetting the fuel economy is the stop/start feature which rather annoyingly cuts the engine as soon as the car is stationary and you're stepping on the brake. The weakness is it cuts out too quickly. No problem normally, but a three-point turn will leave you irritated with an unnecessary blackspot, and leave unsympathetic onlookers laughing up their sleeve as they think you've stalled your expensive motor. It can be disabled, but it reboots as a default setting after you've taken a break.As for the accommodation, I can't fault it. There's plenty of head and knee room for adults in the four main seats, and they're all very comfortable. The boot looks to have a narrow entrance, a high lip and an unhelpful shape, but with some creative packing it consumed a phenomenal amount of luggage.The list of equipment and toys is long, but dominating the car is the multimedia touchscreen that controls the music system, navigation, climate control, heated seats and all sorts of stuff. To me, the screen feels overly cluttered and complicated with too many options, menus and labels.As for the satellite navigation itself – well it may be me, but while working through the city under the guidance of some snooty bint, I was misdirected all over the place. On one occasion she told me I was on a roundabout where there isn't and never has been a roundabout. On several other occasions came the priceless advice to "turn slightly left". How we laughed.A massive gold star, however, goes to the exemplary Bowers and Wilkins 1200W sound system. Seventeen speakers and a subwoofer may sound excessive to you but it sounded like a choir of angels to me. CDs I've listened to for many years revealed subtleties and elements I'd never noticed before. Magnificent.So in conclusion, this is a genuinely head-turning beauty from a much loved and respected marque. It feels like a fine piece of automotive engineering and it's a practical car with a saintly fuel economy. To be succinct, it's put the biggest motoring-induced smile on my face this year.I even enjoyed cursing at that unhelpful bitch of a satnav.Second opinion: Some friends loved the look of the XF (the words "gorgeous" and "sexy" were used), while others didn't think the dark colour suited it. I suspect all of them would have been disappointed by the sound of the diesel engine. This is a very quiet car indeed, but what you can hear isn't particularly attractive, especially under hard acceleration. Perhaps I investigated this too often, because I didn't get anywhere near Mike's economy figure, averaging nearer 40mpg. Straightline performance isn't startling, but there's as much of it as you need, and in most respects the XF is beautifully smooth. Neither the ride nor the handling is helped by the 19" wheels and low-profile tyres of the test car, though I have to say that they coped better on the roads near where I live than they did on the more robust tarmac used for the recent media launch. David Finlay. Engine 2179cc, 4 cylinders Power 187bhp Transmission 8-speed automatic Fuel/CO2 52.3mpg / 149g/km Acceleration 0-62mph: 8.5 seconds Top speed 142 mph Price £43,050 Details correct at publication date