On paper, the petrol-powered QX50 tested here reads like a more exciting prospect than the excellent diesel-engined QX 3.0d that accounts for the bulk of QX50 sales in the UK. And so it is. Take a slightly de-tuned (320PS) version of the 3.7-litre V6 engine found in the wonderful Nissan 370Z sportscar, stick it in a sleekly-styled SUV and shock a few hot hatch jockeys at the traffic lights, with sixty from rest just 6.4s away en route to a maximum speed of around 150mph. The engine makes a lovely noise when you want it to - under hard acceleration - yet is beautifully refined at other times. The ride quality's good too. The diesel version makes 62mph in 7.9s en route to 137mph.
Of course, with a kerb weight of nearly 1900kgs, this is never going to handle like a sportscar, but it never feels tall and tippy in the way a lot of these vehicles can and all the control weights are well judged, the steering feeling precise, very well-oiled and expensive. Not surprisingly though, the QX50 feels most at home on a motorway cruise where you appreciate its exemplary refinement and the V6 engine's wide powerband. The standard 7-speed automatic gearbox perfectly suits its relaxed demeanour, always ready with the right ratio available, although if you do want to take control yourself, you can move the selector over into a push 'n pull channel.
It's hard to pigeonhole the look of this Infiniti. Just when you think you have, you view it from another angle and change your mind. Yes, it's unmistakably an Audi Q5 or Volvo XC60-like prestigious compact SUV - except that unlike those kinds of cars, there's a lovely coupe-like sweep to the rear haunches which compromises luggage space but improves the looks of the car no end. In the same way that a BMW X6 provides a sportier, swoopier option to a boxier X5 in the large luxury 4x4 class above, the QX50 offers the same kind of alternative to squarer rivals in the sector below.
And maybe that's a good thing. After all, to want to buy any Infiniti model, and especially this one, you're going to need to be someone prepared to try something a little different. Inside, there's no argument. The cabin is up-market and attractive, with standard leather trim and now, more than ever, what seems like every automotive gadget known to man. Even the things that other plush brands skimp on like the plastics in areas like the bottom parts of the doors and the seats are of exemplary quality. You won't have any trouble in getting comfortable behind the wheel either, thanks to electrical adjustment for the seats and the steering column. In the back, things aren't quite so spacious and at 340-litres, bootspace is significantly less than you'd get from boxier rivals. Still, at least you can easily make the most of what there is thanks to the way the rear seats go up and down electrically to potentially free up a total of 1175-litres of space.
List prices suggest that you'll likely be paying in the £35,000 to £43,000 bracket for your Infiniti QX50. That puts it up against pricier versions of cars like Audi's Q5, Volvo's XC60 and BMW's X3 but if you're not worried about a prestige nameplate, arguably its closest rival is the Nissan Murano that shares a very similar engine but costs substantially less: such is the price of badge equity.
Infiniti was brave enough to launch its European product line-up with an all-petrol engine range but followed up by offering a modified version of Renault's smooth and torquey 3.0 dCi diesel. It's the 3.7-litre V6 petrol model we're looking at here however, competing as it does with the thirstiest, most powerful petrol versions of obvious BMW, Audi, Volvo and Mercedes rivals.
They all struggle to compete with the kit list of the Infiniti, though. As part of the spec, every QX50 apart from the entry-level 3.0d comes with Infiniti's sophisticated Connectiviti+ navigation and entertainment platform and a premium Bose(r) audio system. Infiniti cites the mid-range GT model in particular as being so complete, it makes an options list all but redundant.
Key features include leather trim, heated, electrically adjustable front seats and electrically adjustable steering column. These are all in addition to the base model features such as intelligent all-wheel-drive, 7-speed automatic transmission, Xenon cornering headlights and electrically foldable rear seat bench - standard on every QX50 including the entry-level QX50 3.0d. GT Premium adds Forward Collision Warning (FCW), Lane Departure Prevention (LDP) and Blind Spot Warning (BSW), an electrically operated glass sunroof, premium Bose(r) audio and 19-inch wheels.
Some QX50 features cannot be had in rivals at any price. Scratch Shield, for example. This unique Infiniti technology ensures the body's gloss finish remains unblemished for years thanks to an elastic resin within the top coat that "fills in" light scratches when exposed to heat. Another clever QX50 touch is the way that you can remotely lower or raise the individual rear seat backrests - highly convenient when it doubles up as an estate car. Equally important for potential owners is the news that Infiniti centres will offer a free collection and delivery service when maintenance or repair work is required - which is just as well for there's a tiny UK dealer network. There's even a helpline to give you advice on all kinds of things when you're out on the road.
Though Infiniti may be a fledgling brand in the UK, the mechanicals used by its models are proven Nissan items through and through, so build quality issues are unlikely. If anything should go wrong, Infiniti has something called 'Total Ownership Experience', intended to guarantee that you'll be treated like royalty, whatever the age of your car. This should all help preserve residual values. These may not be up to the standards of German rivals but then, you're getting a lot more car for your money with the QX50, with a lot more kit fitted as standard. The 3.7-litre engine can return 25mpg on the combined cycle with emissions of 265g/km while the 3.0-litre diesel returns 33.2mpg and 224g/km of CO2.
If your ideal garage would include an SUV, a luxury estate and a luxury sports coupe, then you could argue that this Infiniti QX50 provides all three in one package. You're going to have to accept a few compromises of course and running costs will be high. Still, in compensation, this Infiniti has a pleasingly exclusive feel: it's certainly a car that no one else on your street is likely to have. Which, if you're fed up with the usual choices at the plushest end of the compact 4x4 sector, means that it's probably a car you should try.